Document:

EXHIBIT 10.16b

                First Amendment to Agreement of Purchase and Sale
                -------------------------------------------------
                            (KELLOGG OFFICE BUILDING)

     This First Amendment to Agreement of Purchase and Sale ("First Amendment")
is entered into effective as of November 29, 2001 by and between WXI/MCN
Commercial Real Estate Limited Partnership, a Delaware limited partnership
("Seller") and AmeriVest Properties Inc., a Maryland corporation ("Purchaser").

                                    RECITALS
                                    --------

     WHEREAS, the parties entered into that certain Agreement of Purchase and
Sale ("Agreement") dated October 15, 2001, for the sale of the real property
commonly known as the Kellogg Office Building in Littleton, Colorado
("Property");

     WHEREAS, the Agreement provides for a forty-five (45) day Inspection Period
and a Closing Date of December 28, 2001;

     WHEREAS, the parties now desire to amend the Agreement as set forth herein.

     NOW, THEREFORE, in consideration of the mutual terms and provisions set
forth in the Agreement, the sums to be paid by Purchaser to Seller and for other
good and valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, Purchaser and Seller agree to amend the Agreement as follows:

     1.   The parties hereto agree that as of the effective date of this
          Amendment, both the Inspection Period and Title and Survey Period have
          expired, and Purchaser has elected to proceed to Closing on or before
          December 28, 2001, subject to Seller's satisfaction of the Estoppel
          Contingency (and Purchaser's approval of same) and the Maintenance
          Obligations, both as set forth below.

     2.   On or before December 12, 2001 ("Estoppel Delivery Deadline"), Seller
          shall deliver the tenant estoppel certificates ("Estoppel
          Certificates") to Purchaser in accordance with the provisions of
          Section 4.4 of the Agreement ("Estoppel Contingency"). For a period of
          no more than two (2) business days following Purchaser's receipt of
          all of the Estoppel Certificates from Seller ("Estoppel Review
          Period"), Purchaser shall have the right to review the number, form
          and content of such Estoppel Certificates. In the event (i) Purchaser
          is not satisfied, in its sole and absolute discretion, with any lesser
          number of Estoppel Certificates than the amount Seller is obligated to
          deliver, (ii) any such Estoppel Certificate delivered by Seller is not
          duly executed by the applicable tenant referenced therein, or (iii)
          the form and content of any such Estoppel Certificate delivered by
          Seller materially differs from the form of tenant estoppel certificate
          attached to the Agreement, Purchaser shall have the right to terminate
          the Agreement by delivering written notice of termination to Seller
          and the Escrow Agent on or before the expiration of the Estoppel

                                       1

<PAGE>

          Review Period. If Seller does not receive such written notice of
          termination from Purchaser prior to the expiration of the Estoppel
          Review Period, Purchaser shall be deemed to have approved the Estoppel
          Certificates and the Estoppel Contingency shall be deemed satisfied.

     3.   Prior to Closing, Seller hereby agrees to either: (i) repair on or
          before the Closing Date the following maintenance items relating to
          the Building (the following maintenance items shall be collectively
          referred to herein as the "Maintenance Obligations") (x) replacement
          of the glass panels wherever panels or window seals are broken in
          Suites 160 and 250 of the Building, and (y) installation of backflow
          prevention devices on all water service lines of the Building as
          required by Denver Water Company, which repairs shall be diligently
          performed to Purchaser's satisfaction at least two (2) business days
          prior to Closing; or (ii) credit Purchaser at Closing in a mutually
          agreeable amount for the estimated cost to repair one or both
          Maintenance Obligations, to the extent one or both cannot be
          completely repaired to Purchaser's satisfaction prior to the Closing
          Date.

     4.   Except as expressly amended under this Amendment, all the terms and
          provisions of the Agreement shall remain in full force and effect
          without any modification, waiver or amendment thereto. To the extent
          of any conflict between the terms and provisions of the Agreement and
          this Amendment, the terms and provisions of this Amendment shall
          govern and control.

     5.   All terms which are defined in the Agreement shall have the same
          meaning when used in this Amendment, unless specifically provided
          herein to the contrary.

     6.   This Amendment may be executed in separate counterparts, each of which
          shall constitute an original and all of which, when taken together,
          shall constitute one and the same instrument. In addition, Seller and
          Purchaser agree that facsimile signatures on this Amendment shall be
          deemed effective as originals for all purposes.

                                       2

<PAGE>

     IN WITNESS WHEREOF, the parties hereto have executed this Amendment to be
effective as of the date first written above.

                                            SELLER:
                                            -------

                                            WXL/MCN Commercial Real Estate
                                            Limited Partnership, a Delaware
                                            limited partnership

                                            By: WXI/MCN Commercial Gen-Par, LLC,
                                                a Delaware limited liability
                                                company, its General Partner

                                            By:  /s/  Marijke Lantz
                                               --------------------------------
                                            Name:     Marijke Lantz
                                                 ------------------------------
                                            Title: Assistant Vice President
                                                  -----------------------------

                                            PURCHASER:
                                            ----------

                                            AMERIVEST PROPERTIES INC.
                                            a Maryland Corporation

                                            By:  /s/  John B. Greenman
                                               --------------------------------
                                                      John B. Greenman
                                                      Vice President

                                       3PROMISSORY NOTE
                               (Receivables Loan)

U.S.  $10,000,000                                       Parsippany, New Jersey
                                                       As of November 30, 2001

     FOR VALUE RECEIVED,  the undersigned REGINA RESORTS,  LLC, a Nevada limited
liability   company   ("Maker"),   promises   to  pay  to  RESORT   CONDOMINIUMS
INTERNATIONAL,  LLC, a Delaware limited liability company ("Lender"),  or order,
at  Parsippany,  New  Jersey,  or at such other place as the holder of this Note
("Holder")  may from time to time  designate in writing,  in lawful money of the
United  States of America,  the  principal  sum of TEN MILLION AND NO/100 UNITED
STATES DOLLARS (U.S. $10,000,000),  or so much thereof as has been disbursed and
not repaid,  together with interest on the unpaid principal balance from time to
time  outstanding  from the date hereof until paid,  as more fully  provided for
below.

     This Note is executed  pursuant to a Loan  Agreement  dated as of even date
herewith  between  Maker  and  Lender  (together  with  any and all  extensions,
renewals,   modifications  and  restatements  thereof,   "Loan  Agreement")  and
evidences the advances of the  Receivables  Loan made pursuant  thereto.  Unless
otherwise defined herein,  all capitalized terms used herein shall have the same
meaning as set forth in the Loan Agreement, the specific provisions of which are
incorporated herein by reference as if set forth at length herein.

     Interest  shall accrue  daily on the basis of the actual  number of days in
the computation period using a 360-day year.  Interest shall accrue initially at
the Basic  Interest  Rate in effect on the first day of the month of the initial
advance of the Receivables  Loan and shall adjust  monthly,  on the first day of
each month thereafter,  to equal the Basic Interest Rate in effect on that date,
all as more fully  provided in the Loan  Agreement.  All  principal and interest
payments  due and  owing  under  this Note  shall,  at the time of  payment,  be
"grossed up" by the amount of any Impositions  imposed with respect to this Note
and of principal  and interest  payments due hereunder  (such  amount,  over and
above  the  amount  calculated  at the  Basic  Interest  Rate,  the  "Grossed-up
Interest"), as more fully provided in paragraph 6.1.7 of the Loan Agreement.

     The  contracted  for rate of  interest  of the  Receivables  Loan,  without
limitation,  may  consist  of  the  following:  (i)  the  Basic  Interest  Rate,
calculated and applied to the principal  balance of this Note in accordance with
the  provisions  of this Note and the Loan  Agreement;  (ii) the  Default  Rate,
calculated and applied to the amounts due under this Note in accordance with the
provisions of this Note and Loan Agreement;  (iii) the Grossed-Up Interest;  and
(iv) all Additional  Sums (as hereinafter  defined),  if any. In accordance with
the Loan  Agreement and this Note,  Maker agrees to pay an effective  contracted
for rate of interest that is the sum of the above referenced elements.

     All fees,  charges,  goods, things in action or any other sums or things of
value (other than amounts described in the immediate previous  paragraph),  paid
or payable by Maker (collectively,  the "Additional Sums"),  whether pursuant to
this Note,  the Loan  Agreement or the other  Receivables  Loan Documents or any
other   documents  or   instruments  in  any  way  pertaining  to  this  lending
transaction,  or otherwise with respect to this lending transaction,  that under
any  applicable  law may be deemed to be interest  with  respect to this lending
transaction,  for the purpose of any  applicable  law that may limit the maximum
amount of interest to be charged with respect to this  lending  transaction,  is
payable  by Maker as,  and is deemed to be,  additional  interest,  and for such
purposes  only,  the agreed upon and  "contracted  for rate of interest" of this
lending  transaction is deemed to be increased by the rate of interest resulting
from the inclusion of the Additional Sums.

     Payments of principal and/or interest shall earn interest,  commencing five
(5) Business  Days after they are due, at the Default Rate computed on the basis
of actual number of days elapsed  using a 360-day  year. In addition,  after the
occurrence of an Event of Default  regardless of whether such occurrence results
in an  acceleration  of the amounts due under this Note,  but solely  during the
continuance  of such  Event  of  Default,  interest  shall  accrue  on the  then
principal  balance of this Note at the Default Rate calculated in the manner set
forth above.

     In no event  shall the  interest  payable  on this  Note and other  charges
payable in the nature of interest  exceed the maximum  contract  rate  permitted
under the Applicable Usury Law.

     Commencing  on the last  Business Day of the month during which the initial
advance of the  Receivables  Loan is made and on the last day of each succeeding
month thereafter  ("Installment  Date") until the Receivables Loan Maturity Date
or the date the Receivables  Loan is paid in full,  whichever date first occurs,
Maker will pay or cause to be paid to Holder an installment payment of principal
and interest in the amounts required to be paid pursuant to paragraph 2.7 of the
Loan Agreement.

     Regardless  of whether  the  proceeds  of the  Receivables  Collateral  are
sufficient for that purpose,  interest on the principal balance hereof from time
to time  outstanding  shall  be due  and  payable  monthly  in  arrears  on each
Installment Date; and principal  payments on the Note in the amounts required to
be paid pursuant hereto or to paragraphs 2.1 and 3.2 of the Loan Agreement shall
be due and payable at the times specified in such paragraphs.

     On the Receivables Loan Maturity Date, the entire unpaid principal  balance
of this Note,  all accrued and unpaid  interest,  and all other charges owing in
connection with the Receivables Loan shall be due and payable in full.

     In the event an Event of Default  occurs,  Holder  may,  without  notice or
demand,  declare immediately due and payable the entire unpaid principal balance
hereof, all accrued and unpaid interest thereon,  and all other charges owing in
connection with the Receivables Loan.

     Prepayment  of this  Note is  permitted  in  whole  or in part at any  time
without premium or penalty.

     In the event that  Holder  employs  the  services of an attorney to enforce
this Note, Maker agrees to pay to Holder in addition to any indebtedness due and
unpaid,   all  costs  and  expenses  of  such  proceedings,   including  without
limitation,  attorneys' and paralegals'  fees and costs and expert witness fees,
all as more fully set forth in the Loan Agreement.

     Holder  shall not by any act of omission or  commission  be deemed to waive
any of its rights or  remedies  hereunder  unless  such waiver be in writing and
signed  by an  authorized  officer  of  Holder  and  then  only  to  the  extent
specifically set forth therein;  a waiver on one occasion shall not be construed
as  continuing  or as a bar to or  waiver  of such  right or remedy on any other
occasion.  All  remedies  conferred  upon  Holder  by  this  Note  or any  other
instrument or agreement connected herewith or related hereto shall be cumulative
and none is  exclusive,  and such  remedies  may be  exercised  concurrently  or
consecutively at Holder's option.

     Every  person  or  entity  at  any  time  liable  for  the  payment  of the
indebtedness  evidenced  hereby waives:  presentment for payment;  protest;  and
notice of protest, dishonor and/or nonpayment of this Note. Every such person or
entity  further  consents that Holder may renew or extend the time of payment of
any part or the whole of the  indebtedness  at any time and from time to time at
the  request of any  person or entity  liable  therefor.  Any such  renewals  or
extensions  may be made  without  notice to any person or entity  liable for the
payment of the indebtedness evidenced hereby.

     This Note is given and accepted as evidence of indebtedness only and not in
payment or satisfaction of any indebtedness or obligation.

     Time is of the  essence  with  respect  to all of Maker's  obligations  and
agreements under this Note.

     This Note and all its provisions, conditions, promises and covenants hereof
shall be binding in accordance with the terms hereof upon Maker,  its successors
and assigns,  provided  nothing herein shall be deemed consent to any assignment
restricted or prohibited  by the terms of the Loan  Agreement.  If more than one
person or other entity has executed this Note as Maker,  the obligations of such
persons and entities shall be joint and several.

     THIS NOTE AND THE RIGHTS,  DUTIES AND  OBLIGATIONS  OF THE  PARTIES  HERETO
SHALL BE GOVERNED BY AND CONSTRUED IN  ACCORDANCE  WITH THE INTERNAL LAWS OF THE
STATE OF NEW JERSEY  (WITHOUT  REGARD TO CONFLICTS OF LAWS PRINCIPLES THAT WOULD
CALL FOR THE  APPLICATION  OF THE  LAWS OF ANY  OTHER  JURISDICTION)  AND TO THE
EXTENT THEY PREEMPT THE LAWS OF SUCH STATE, THE LAWS OF THE UNITED STATES.

     EACH OF MAKER AND  HOLDER:  (A) HEREBY  IRREVOCABLY  SUBMITS  ITSELF TO THE
PROCESS, JURISDICTION AND VENUE OF THE COURTS OF THE STATE OF NEW JERSEY, MORRIS
COUNTY,  AND TO THE PROCESS,  JURISDICTION,  AND VENUE OF THE NEWARK DIVISION OF
THE  UNITED  STATES  DISTRICT  COURT FOR THE  DISTRICT  OF NEW  JERSEY,  FOR THE
PURPOSES OF SUIT, ACTION OR OTHER PROCEEDINGS ARISING OUT OF OR RELATING TO THIS
NOTE OR THE SUBJECT  MATTER HEREOF;  AND (B) WITHOUT  LIMITING THE GENERALITY OF
THE FOREGOING,  HEREBY WAIVES AND AGREES NOT TO ASSERT BY WAY OF MOTION, DEFENSE
OR OTHERWISE  IN ANY SUCH SUIT,  ACTION OR  PROCEEDING  ANY CLAIM THAT IT IS NOT
PERSONALLY  SUBJECT TO THE  JURISDICTION  OF THE ABOVE-NAMED  COURTS,  THAT SUCH
SUIT, ACTION OR PROCEEDING IS BROUGHT IN AN INCONVENIENT FORUM OR THAT THE VENUE
OF SUCH SUIT, ACTION OR PROCEEDING IS IMPROPER.

                [Remainder of this page intentionally left blank]

<PAGE>

     HOLDER AND MAKER ACKNOWLEDGE AND AGREE THAT ANY CONTROVERSY WHICH MAY ARISE
UNDER THIS NOTE WOULD BE BASED UPON DIFFICULT AND COMPLEX ISSUES; AND THEREFORE,
THEY AGREE THAT ANY LAWSUIT ARISING OUT OF ANY SUCH  CONTROVERSY  SHALL BE TRIED
BY A JUDGE SITTING WITHOUT A JURY, AND KNOWINGLY AND VOLUNTARILY  WAIVE TRIAL BY
JURY IN ANY SUCH PROCEEDING.

     ALL OF THE  PROVISIONS SET FORTH IN THE PREVIOUS THREE (3) PARAGRAPHS ARE A
MATERIAL INDUCEMENT FOR HOLDER'S MAKING ADVANCES TO MAKER.

                                                  (MAKER'S INITIALS RE PREVIOUS
                                                FOUR (4) PARAGRAPHS:  _________)

                            [SIGNATURE PAGE FOLLOWS]

<PAGE>

             [SIGNATURE PAGE FOR PROMISSORY NOTE (RECEIVABLES LOAN)]

                                   REGINA RESORTS, LLC, a Nevada limited
                                              liability company

                                   By: CR Resorts Los Cabos, S. de R.L. de C.V.,
                                       a Mexican limited responsibility
                                       corporation with variable capital

                                   Its:    Managing Member

                                   By:   /s/ Guestavo Ripol
                                       -------------------------------------
                                             Name:  Gustavo Ripol Bermudez
                                                Title:  Attorney-in-Fact

                                                           "Maker"

                                  Address of Maker:

                                  REGINA RESORTS, LLC
                                  Blvd. Adolfo Ruiz Cortines No. 3642-7
                                  Col. Jardines del Pedregal
                                  Mexico, Distrito Federal 01900
                                     Mexico

                                  _____ Check here to confirm that
                                  last paragraph has been initialed.

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