<PAGE>   1
                                                                  Exhibit 10(rr)
                                                                       conformed

                            SHARE EXCHANGE AGREEMENT

            SHARE EXCHANGE AGREEMENT, dated as of February 13, 1999, by and
among TPG Partners II, L.P., a Delaware limited partnership ("TPG Partners"),
TPG Parallel II, L.P., a Delaware limited partnership ("TPG Parallel"), TPG
Investors II, L.P., a Delaware limited partnership ("TPG Investors", and
together with TPG Partners and TPG Parallel, "TPG"), Chase Equity Associates,
L.P., a Delaware limited partnership ("Chase"), Oxford Acquisition Corp., a
Delaware corporation ("Acquisition"), the entities listed as "DLJ Entities" on
the signature pages hereto (each, a "DLJ Entity," and together with TPG, Chase
and Acquisition, the "Investors") and Oxford Health Plans, Inc., a Delaware
corporation (the "Company").

            WHEREAS, the Company desires to exchange (i) newly-issued shares of
its Series D Cumulative Preferred Stock, par value $0.01 per share (the "Series
D Preferred Stock"), for all of the outstanding shares of its Series A
Cumulative Preferred Stock, par value $0.01 per share (the "Series A Preferred
Stock"), and (ii) newly-issued shares of its Series E Cumulative Preferred
Stock, par value $0.01 per share (the "Series E Preferred Stock," and together
with the Series D Preferred Stock, the "New Preferred Stock"), for all
outstanding shares of its Series B Cumulative Preferred Stock, par value $0.01
per share (the "Series B Preferred Stock," and together with the Series A
Preferred Stock, the "Existing Preferred Stock");

            WHEREAS, the Investors desire to exchange all outstanding shares of
the Existing Preferred Stock for newly-issued shares of the New Preferred Stock;
and

            WHEREAS, the Investors and the Company desire to amend the
Assignment Agreements (as defined below), the Investment Agreement (as defined
below), the Registration Rights Agreement (as defined below) and the Warrants
(as defined below) in connection with the transactions contemplated hereby;

            NOW, THEREFORE, in consideration of the premises and the mutual
agreements set forth herein, the parties hereto agree as follows:

            Section 1. Series A Exchange. The Company shall issue, in the
aggregate, 260,146.909 shares of Series D Preferred Stock having the rights,
preferences, privileges and restrictions set forth in the form of Certificate of
Designations attached hereto as Exhibit A and shall exchange all such shares
with the Investors for all outstanding shares of Series A Preferred Stock. Each
Investor agrees to participate in the exchange described in the preceding
sentence by surrendering to the Company all outstanding shares of Series A
Preferred Stock held by such Investor at such place as the Company shall
designate in its reasonable discretion and upon such surrender to accept a
corresponding number of shares of Series D Preferred Stock in exchange therefor.

            Section 2. Series B Exchange. The Company shall issue, in the
aggregate, 111,820.831 shares of Series E Preferred Stock having the rights,
preferences, privileges and restrictions set forth in the form of Certificate of
Designations attached hereto as Exhibit B and shall exchange all such shares
with the Investors for all outstanding shares of Series B Preferred Stock. Each
Investor agrees to participate in the exchange described in the preceding
sentence by
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surrendering to the Company all outstanding shares of Series B Preferred Stock
held by such Investor at such place as the Company shall designate in its
reasonable discretion and upon such surrender to accept a corresponding number
of shares of Series E Preferred Stock in exchange therefor.

            Section 3. Time of Exchange. The share exchanges described in
Sections 1 and 2 hereof shall occur on February 13, 1999 (the "Exchange Date").
The obligation of any party hereto to participate in either of the exchanges
described in Sections 1 and 2 hereof shall be conditioned on the other exchange
occurring simultaneously.

            Section 4. Effectiveness; Counterparts. This Share Exchange
Agreement shall become effective when executed by each of the parties hereto.
This Share Exchange Agreement may be executed in any number of separate
counterparts, each of which shall, collectively and separately, constitute one
agreement.

            Section 5. Assignment Agreement Amendments. Reference is made to the
Assignment Agreement, dated April 23, 1998, among TPG Oxford LLC, a Delaware
limited liability company ("TPG Oxford") and the DLJ Entities, the Assignment
Agreement, dated April 28, 1998, between TPG Oxford and Acquisition, and the
Assignment Agreement, dated April 28, 1998, between TPG Oxford and Chase
(collectively, the "Assignment Agreements"). Each Investor agrees with respect
to the Assignment Agreement or Assignment Agreements to which such Investor is a
party that from and after the consummation of the exchanges referred to in
Sections 1 and 2 hereof:

            (a) All references in such Agreement or Agreements relating to the
"Series A Preferred Stock" and "Series B Preferred Stock" shall be deemed to be
references to the Series D Preferred Stock and Series E Preferred Stock,
respectively.

            (b) An additional section shall be added to such Agreement or
Agreements which states: "Each party hereto agrees that prior to May 13, 2000
such party and its transferees, successors and assigns shall not use shares of
Series D Preferred Stock as consideration in connection with the exercise of the
Series A Warrants or Series B Warrants; provided, that such party and its
transferees, successors and assigns in the aggregate may do so with respect to a
percentage of the total number of shares of the Series D Preferred Stock
originally issued by the Company to such party on the Exchange Date that does
not exceed the percentage of the total number of shares of Series E Preferred
Stock issued by the Company on the Exchange Date that have been (A) redeemed by
the Company, (B) repurchased by the Company as a result of a Change of Control
(as defined in the Certificate of Designations for the Series E Preferred Stock)
or otherwise, (C) used as consideration in connection with the exercise of the
Company's Series A Warrants or Series B Warrants, or (D) otherwise retired by
the Company.

            Section 6. Investment Agreement, Registration Rights Agreement and
Warrant Amendments. (a) Reference is made to the Investment Agreement, dated as
of February 23, 1998 (the "Investment Agreement"), by and between TPG Oxford and
the Company. From and after the consummation of the exchanges referred to in
Sections 1 and 2 hereof, all references set forth in the Investment Agreement to
the "Series A Cumulative Preferred Stock, par value $0.01
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per share", "Series A Preferred Stock" and the "Series A Certificate of
Designations" shall be deemed to be references to the Series D Cumulative
Preferred Stock, par value $0.01 share, Series D Preferred Stock and the
Certificate of Designations filed with the Secretary of State of the State of
Delaware with respect to the Series D Preferred Stock, respectively. From and
after the consummation of the exchanges referred to in Sections 1 and 2 hereof,
all references set forth in the Investment Agreement to the "Series B Cumulative
Preferred Stock, par value $0.01 per share", "Series B Preferred Stock" and the
"Series B Certificate of Designations" shall be deemed to be references to the
Series E Cumulative Preferred Stock, par value $0.01 per share, Series E
Preferred Stock and the Certificate of Designations filed with the Secretary of
State of the State of Delaware with respect to the Series E Preferred Stock,
respectively.

            (b) Reference is made to the Registration Rights Agreement, dated as
of February 23, 1998 by and between the Company and TPG Oxford (the
"Registration Rights Agreement"). From and after the consummation of the
exchanges referred to in Sections 1 and 2 hereof, all references set forth in
the Registration Rights Agreement to the "Series A Cumulative Preferred Stock,
par value $0.01 per share" and the "Series A Preferred Stock" shall be deemed to
be references to the Series D Cumulative Preferred Stock, par value $0.01 per
share and the Series D Preferred Stock, respectively. From and after the
consummation of the exchanges referred to in Sections 1 and 2 hereof, all
references set forth in the Registration Rights Agreement to the "Series B
Cumulative Preferred Stock, par value $0.01 per share" and the "Series B
Preferred Stock" shall be deemed to be references to the Series E Cumulative
Preferred Stock, par value $0.01 per share and the Series E Preferred Stock,
respectively.

            (c) Reference is made to the Series A Warrants and Series B Warrants
of the Company, dated May 13, 1998 (collectively, the "Warrants"). As of the
date hereof, all outstanding Warrants are held by the Investors. From and after
the consummation of the exchanges referred to in Sections 1 and 2 hereof, all
references set forth in the Warrants to the "Series A Cumulative Preferred
Stock, par value $0.01 per share", "Series A Preferred Stock" and the
"Certificate of Designations for the Series A Preferred Stock filed by the
Company with the Secretary of State of the State of Delaware" shall be deemed to
be references to the Series D Cumulative Preferred Stock, par value $0.01 per
share, Series D Preferred Stock and the Certificate of Designations filed with
the Secretary of State of the State of Delaware with respect to the Series D
Preferred Stock, respectively. From and after the consummation of the exchanges
referred to in Sections 1 and 2 hereof, all references set forth in the Warrants
to the "Series B Cumulative Preferred Stock, par value $0.01 per share", "Series
B Preferred Stock" and the "Certificate of Designations for the Series B
Preferred Stock filed by the Company with the Secretary of State of the State of
Delaware" shall be deemed to be references to the Series E Cumulative Preferred
Stock, par value $0.01 per share, Series E Preferred Stock and the Certificate
of Designations filed with the Secretary of State of the State of Delaware with
respect to the Series E Preferred Stock, respectively.

            Section 7. Binding Effect; Transfers. Each Investor agrees that this
Agreement and the obligations hereunder shall attach to all of such Investor's
shares of Existing Preferred Stock and shall be binding upon any person or
entity to which legal or beneficial ownership of such shares shall pass, whether
by operation of law or otherwise, including, without limitation, such Investor's
heirs, guardians, administrators or successors.


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            Section 8. Governing Law. This Share Exchange Agreement shall be
governed by, and construed and enforced in accordance with, the laws of the
State of New York, without regard to the principles thereof regarding conflicts
of law.


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            IN WITNESS WHEREOF, the parties hereto have caused this Share
Exchange Agreement to be executed by their respective officers or partners
thereunto duly authorized, as of the date first above written.


                                    OXFORD HEALTH PLANS, INC.


                                    By:  /s/ Jeffery H. Boyd
                                         -----------------------------
                                    Name: Jeffery H. Boyd
                                    Title: EVP, General Counsel


                                    TPG PARTNERS II, L.P.

                                    By:   TPG GenPar II, L.P.
                                          General Partner

                                          By:   TPG Advisors II, Inc.
                                                General Partner


                                    By:   /s/ James O'Brien
                                       -----------------------------------
                                    Name:  James J. O'Brien
                                    Title:    Vice President


                                       5
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                                    TPG PARALLEL II, L.P.

                                    By:   TPG GenPar II, L.P.
                                          General Partner

                                          By:   TPG Advisors II, Inc.
                                                General Partner

                                    By:  /s/ James O'Brien
                                         ---------------------------
                                    Name:  James J. O'Brien
                                    Title:    Vice President


                                    TPG INVESTORS II, L.P.

                                    By:   TPG GenPar II, L.P.
                                          General Partner

                                          By:   TPG Advisors II, Inc.
                                                General Partner

                                    By: /s/ James O'Brien
                                        ---------------------------
                                    Name:  James J. O'Brien
                                    Title:    Vice President



                                    CHASE EQUITY ASSOCIATES, L.P.

                                          By:   Chase Capital Partners
                                                General Partner


                                    By: /s/ Mitchell J. Butt
                                        -----------------------------
                                    Name:  Mitchell J. Butt
                                    Title: Executive Partner


                                    OXFORD ACQUISITION CORP.

                                    By: John D. Howard
                                        -----------------------------
                                    Name:  John D. Howard
                                    Title: Executive Vice President


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<PAGE>   7
                                  DLJ ENTITIES:

                                  DLJMB FUNDING II, INC.


                                           /s/ Ivy Dodes
                                           ------------------
                                           Name: Ivy Dodes
                                           Title: Vice President

                                      DLJMB FUNDING II, INC.

                                           /s/ Ivy Dodes
                                           ------------------
                                           Name: Ivy Dodes
                                           Title: Vice President

                                      DLJ MERCHANT BANKING PARTNERS II-A, L.P.

                                      By: DLJ Merchant Banking II, Inc.
                                          Managing General Partner


                                           /s/ Ivy Dodes
                                           ------------------
                                           Name: Ivy Dodes
                                           Title: Vice President


                                      DLJ DIVERSIFIED PARTNERS, L.P.

                                      By: DLJ Diversified Partners, L.P.
                                             Managing General Partner

                                       /s/ Ivy Dodes
                                       -------------------------
                                           Name: Ivy Dodes
                                           Title: Vice President


                                       7
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                                      DLJ DIVERSIFIED PARTNERS-A, L.P.

                                      By: DLJ Diversified Partners, L.P.
                                          Managing General Partner

                                        /s/ Ivy Dodes
                                      ------------------------
                                           Name: Ivy Dodes
                                           Title: Vice President


                                      DLJ MILLENIUM Partners, L.P.

                                      By: DLJ Merchant Banking II, Inc.
                                          Managing General Partner


                                           /s/ Ivy Dodes
                                           ------------------
                                           Name: Ivy Dodes
                                           Title: Vice President

                                      DLJ MILLENIUM Partners-A, L.P.

                                      By: DLJ Merchant Banking II, Inc.
                                          Managing General Partner


                                           /s/ Ivy Dodes
                                           ------------------
                                           Name: Ivy Dodes
                                           Title: Vice President


                                      DLJ FIRST ESC L.P.

                                      By: DLJ LBO Plans Management
                                          Corporation
                                          General Partner


                                           /s/ Ivy Dodes
                                           ------------------
                                           Name: Ivy Dodes
                                           Title: Vice President


                                       8
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                                      DLJ OFFSHORE PARTNERS II, C.V.

                                      By: DLJ Merchants Banking II, Inc.
                                          Managing General Partner


                                           /s/ Ivy Dodes
                                           ------------------
                                           Name: Ivy Dodes
                                           Title: Vice President


                                      DLJ EAB PARTNERS, L.P.

                                      By: DLJ LBO Plans Management
                                          Corporation
                                          General Partner

                                           /s/ Ivy Dodes
                                           ------------------
                                           Name: Ivy Dodes
                                           Title: Vice President


                                      UK INVESTMENT PLAN 1997 PARTNERS

                                           /s/ Ivy Dodes
                                           ------------------
                                           Name: Ivy Dodes
                                           Title: Vice President

                                      By: UK Investment Plan 1997 Partners, Inc.
                                          Managing General Partner

                                             /s/ Ivy Dodes
                                             ------------------
                                             Name: Ivy Dodes
                                             Title: Vice President


                                       9
<PAGE>   10
                                      DLJ ESC II L.P.

                                      By: DLJ LBO Plans Management
                                          Corporation
                                          Manager


                                             /s/ Ivy Dodes
                                             --------------------------
                                             Name: Ivy Dodes
                                             Title: Vice President



                                      DLJ CAPITAL CORPORATION

                                             /s/ Ivy Dodes
                                             --------------------------
                                             Name: Ivy Dodes
                                             Title: Vice President


                                      SPROUT GROWTH II, L.P.

                                      By: DLJ Capital Corporation
                                          Managing General Partner

                                             /s/ Arthur S. Zuckerman
                                             --------------------------
                                             Name: Arthur S. Zuckerman
                                             Title: Vice President


                                      THE SPROUT CEO FUND, L.P.

                                      By: DLJ Capital Corporation
                                          General Partner

                                             /s/ Arthur S. Zuckerman
                                             --------------------------
                                             Name: Arthur S. Zuckerman
                                             Title: Vice President


                                       10
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                                      SPROUT CAPITAL VIII, L.P.

                                      By: DLJ Capital Corporation
                                          Managing General Partner

                                             /s/ Arthur S. Zuckerman
                                             --------------------------
                                             Name: Arthur S. Zuckerman
                                             Title: Vice President



                                      SPROUT VENTURE CAPITAL, L.P.

                                      By: DLJ Capital Corporation
                                          General Partner

                                             /s/ Arthur S. Zuckerman
                                             --------------------------
                                             Name: Arthur S. Zuckerman
                                             Title: Vice President


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