Document:

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                                                                   EXHIBIT 10.11

                               AMENDMENT TO LEASE

     THIS AMENDMENT TO LEASE is entered into this 31st day of July, 1996, by and
between TRANSCONTINENTAL REALTY INVESTORS, INC., (hereinafter called "LANDLORD")
and AAXICO SALES, INC. AND SATELLITE ACCESS SYSTEMS, INC. (hereinafter called
"TENANT");

                                  WITNESSETH;

     WHEREAS, the LANDLORD and TENANT have previously entered into a Lease dated
this 1st day of July, 1996, premises containing approximately 11,146 square feet
and located at 111 Second Avenue NE, in St. Petersburg, FL (hereinafter referred
to as the "Original Lease"); and

     WHEREAS, LANDLORD and TENANT are desirous of modifying and amending certain
parts of the Original Lease;

     NOW THEREFORE, in consideration of the mutual promises and obligations
contained herein, the adequacy and sufficiency of which is hereby acknowledged,
it is agreed by and between the parties that the Lease shall be hereby amended
in the following manner and upon the terms and conditions hereinafter set forth:

          Tenant shall be allowed, at Tenant's cost, to submeter the building
          HVAC system to allow air conditioning to the premises during non
          standard building hours. Tenant agrees to pay after hours air
          conditioning charges directly to Florida Power. Tenant further agrees
          to share the cost of all maintenance and repair of the 16th floor HVAC
          system, with Tenant responsible for 61% and the Landlord responsible
          for 39% of the cost. Tenant acknowledges that the HVAC system is
          turned off from time to time for regular maintenance and repairs and
          that Landlord will provide Tenant with reasonable notice whenever
          possible.

Except as provided herein, all other terms, conditions, and covenants under said
Original Lease shall remain in full force and effective and cannot be modified
unless said modification is reduced to writing and signed by all parties.

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<CAPTION>

<S>                                                    <C>
LANDLORD:                                              TENANT:
Transcontinental Realty Investors, Inc.                AAXICO SALES, INC.

By: /s/ David W. Starowicz                             By: Illegible
   -------------------------------------                  -------------------------------
   David W. Starowicz                                     TITLE:
   Vice President

DATE: 8/16/96                                           Date: July 25, 1996
      ----------------------------------                      ---------------------------

WITNESS: /s/ Michelle C. McDowell                       WITNESS: Illegible
        --------------------------------                        -------------------------

WITNESS: Illegible                                      WITNESS: Illegible
        --------------------------------                        -------------------------

                                                        TENANT:
                                                        SATELLITE ACCESS SYSTEMS, INC.

                                                        By: Illegible
                                                            -----------------------------
                                                            TITLE: CEO

                                                        DATE: July 22, 1996
                                                              ---------------------------

                                                        WITNESS: Illegible
                                                                 ------------------------

                                                        WITNESS: Illegible
                                                                 ------------------------
</TABLE><PAGE>   1
                                                                   EXHIBIT 10.12

                            SQUARE FOOTAGE AMENDMENT

     THIS SQUARE FOOTAGE AMENDMENT (this "Amendment") dated as of this 7th day
of May, 1999 amending that certain Lease Agreement dated March 22, 1999 and any
and all Letters of Agreement, Addenda, Amendments or Extensions thereof
(collectively, the "Lease") by and between SAWGRASS PLAZA ASSOCIATES
("Landlord") and CORSAIRE, INC., ("Tenant").

                              W I T N E S S E T H:

     WHEREAS, Landlord and Tenant entered into the Lease relating to certain
office space (the "Premises") within the building known as Sawgrass Plaza (the
"Building") located at 1550 Sawgrass Corporate Parkway, Sunrise, Florida; and

     WHEREAS, subsequent to the date of the Lease, the actual square footage of
the Premises has been measured according to the current B.O.M.A. standard for
square footage calculation; and

     NOW, THEREFORE, for and in considerations of the terms, covenants and
conditions hereinafter set forth, and for other good and valuable
consideration, the receipt and sufficiency of which is hereby acknowledged,
Landlord and Tenant agree as follows:

1.   Notwithstanding anything contained in the Lease, as amended, to the
     contrary, the Premises shall mean 3,433 rentable square feet comprising the
     second (2nd) floor of the Building known as Suite 220.

2.   The Base Rent, Additional, Tenant Improvement Allowance and all other
     amounts specified in the Lease which are a function of the rentable square
     footage of the Premises shall be adjusted accordingly.

     All other terms and conditions of the Lease not amended hereby are in full
force and effect and binding upon the parties thereto.

     Any provision of this Amendment shall prevail over conflicting provisions
contained in the Lease.

     IN WITNESS WHEREOF, the parties have executed this Amendment as of the day
and year first above written.

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<S>                                               <C>
Signed, sealed and delivered
in the presence of:                               Sawgrass Plaza Associates,
                                                  a Florida general partnership
Illegible                                         through its authorized agent,
---------------------------------                 Stiles Corporation

/s/ Janet M. Nathon                               By: /s/ Rocco Ferrera
---------------------------------                    ---------------------------
                                                     Rocco Ferrera,
                                                     Vice President

                                                         "TENANT"

Signed, sealed and delivered
in the presence of:                               CORSAIRE, INC., a Delaware corporation
                                                  d/b/a Net Command Tech, Inc.

Illegible                                         By: /s/ William K. Dunavant
---------------------------------                     -------------------------

Illegible                                         President/Dunavant
---------------------------------                 -----------------------------
                                                  Print Name and Title
</TABLE><PAGE>   1
                                                                   EXHIBIT 10.13

                                    ADDENDUM

THIS ADDENDUM ("Addendum") entered into this 1st day of March, 1999, by and
between Net Command Tech, Inc. (f/k/a Corsaire, Inc.), a Delaware corporation
("Company") with offices at 62 Indian Trace, Weston, Florida 33326 and Robert
Chalnick ("Executive"), with an address of 1021 Northwest 108th Avenue,
Plantation, Florida 33322.

                              W I T N E S S E T H:

WHEREAS, the Company and the Executive have entered into an Employment
Agreement ("Agreement") on this same date; and

WHEREAS, the Company and Executive have agreed that this Addendum shall form a
part of the Agreement;

NOW, THEREFORE, in consideration of the mutual promises contained herein and in
the Agreement and other good and valuable consideration, the receipt and
sufficiency of which is hereby acknowledged, the parties agree as follows:

1.   PRECEDENCE AND INCORPORATION. This Addendum forms a part of the Agreement
attached. The Agreement and this Addendum shall be considered one document. The
terms contained in this Addendum shall take precedence over any Agreement terms
that are inconsistent with this Addendum. Terms used in this Addendum shall
have the same meaning as ascribed to them in the Agreement.

2.   INTERIM BASE SALARY REVIEW. Executive's Base Salary shall be reviewed for
an interim increase on July 1, 1999.

3.   SEPARATION PAY. Executive shall be entitled to receive twelve (12) month's
pay as separation pay in the event of Executive's termination of employment
with the Company, so long as Executive is not terminated with cause, as that
term is defined in Paragraph 6 of the Agreement. Executive shall also receive
any bonus earned (pro-rata) at the time of termination, so long as Executive is
not terminated with cause, as that term is defined in Paragraph 6 of the
Agreement. Payment shall be made, in the Company's sole discretion, in a lump
sum or periodic payments over six months. Executive's life, medical, and other
insurance coverages shall be maintained at the Company's expense for a period
of twelve (12) months or until such time that Executive obtains new full time
employment, so long as Executive is not terminated with cause, as that term is
defined in Paragraph 6 of the Agreement.

The Company has no severance pay policy or plan and this separation pay shall
not be considered severance pay. However, this paragraph 3 shall survive
termination of the Agreement, provided that it is not terminated under
Paragraph 6 of the Agreement.

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4.   STOCK ISSUANCE. Executive shall be issued two hundred fifty thousand
(250,000) shares of the Company's common stock at a price of $.001 per share
upon execution of this Agreement. These shares shall be registered by the
Company if Executive is terminated without cause.

5.   STOCK OPTIONS. Executive shall receive cashless options for two hundred
fifty thousand (250,000) shares at a price of $5.00 per share, with 10,000
vesting per month for the first twenty-five (25) months of employment. Should
Executive be terminated without cause, or terminated or demoted because of a
corporate reorganization and/or takeover/acquisition, or should there be a
change in control of fifty-one-percent (51%) or more by a single shareholder or
shareholder group (all these described events collectively defined as ("Control
Event"), all options accrued at the time of the Control Event shall vest
immediately. Executive shall also be eligible to participate in the Company's
Incentive Stock Option Program.

6.   BENEFITS. Executive shall receive the following fringe benefits in
addition to his base benefits, which shall be vested upon Executive's
commencement of employment with the Company:

               A.   Four weeks paid vacation during the first year of the
Initial Term. Five weeks paid vacation each year thereafter. Unused vacation
days in any year can be carried over and accumulated to subsequent years.

               B.   Six (6) personal/sick days each year and up to six days off
per year for national holidays, such holidays being in addition to vacation
days.

               C.   Health Insurance (PPO), Dental Insurance, Disability
Insurance, and Life Insurance in the amount of $500,000.00 for Executive and
his dependents. Company shall pay all premiums required for these coverages.

               D.   Participation in the Company's 401K Plan, with matching
contributions made annually by the Company up to two-percent (2%) of
Executive's Base Salary for each year.

               E.   A Company vehicle, leased not to exceed $800 per month,
with the Company paying all lease, gasoline, maintenance and insurance costs.

               F.   Club membership fees up to a maximum of $3,500 per year.

               G.   Tax accounting reimbursement up to $1,500 per year, for
personal advisory services regarding Company stock and income tax filing.

               H.   Company shall pay Executive's attendance at seminars and
conferences that will enhance the Company's reputation, standing, or
profitability. Attendance at the described events shall not be categorized as
sick, personal, or vacation days.

               I.   Company shall pay Executive's professional due and
continuing professional education requirements for Executive's retention as a
Certified Public Accountant. Professional education under this paragraph shall
not be categorized as sick, personal, or vacation days.

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<PAGE>   3
7.   RELOCATION. If Executive agrees to a relocation from his present employment
locale and domicile, Company shall reimburse Executive for all relocation
expenses typical for executives, including domicile closing costs, points and
commissions, with the intent that executive does not incur any financial loss
in the overall cost of the relocation, with the exception of purchase and sale
prices of his changes in domiciles.

8.   COUNTERPARTS. This Addendum may be executed in counterparts, each of which
shall be deemed an original. All such counterparts together shall constitute
one and the same Agreement.

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

NET COMMAND TECH, INC.                       "Executive"

By: /s/ William R. Dunavant                  /s/ Robert Chalnick
   ------------------------------            ---------------------------
   William R. Dunavant, President            Robert Chalnick

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