Exhibit 4.6
                                                                     -----------
                               Amendment Number 6
                                       to
                        PCS U.S. Employees' Savings Plan

         WHEREAS, PCS Administration (USA), Inc. (the "Sponsor") maintains the
PCS U.S. Employees' Savings Plan (the "Plan"), a qualified defined contribution
plan pursuant to section 401(a) of the Internal Revenue Code of 1986; and

         WHEREAS, the Sponsor desires to amend the Plan to suspend employer
matching contributions under the Plan and to include Actual Deferral Percentage
("ADP") testing provisions in the Plan document; and

         WHEREAS, pursuant to Section 12.3 of the Plan, the Sponsor may amend
the Plan at any time, and has authorized its officers to execute this amendment
to the Plan;

         NOW THEREFORE, BE IT RESOLVED, that effective August 1, 2003 the Plan
is amended as follows:

1. Section 1.1 of the Plan is hereby amended by adding the following as the last
paragraph of that section:

         "Effective August 1, 2003, the Plan is no longer intended to meet the
         safe harbor discrimination testing rules of Code sections 401(k)(12)
         and 401(m)(11)."

2. Section 3.5 of the Plan is hereby amended by adding a new subsection (c) to
that Section immediately following subsection (b), to read as follows:

         "(c) Effective August 1, 2003 and for Plan Years beginning thereafter,
         the notice provided for in this section shall no longer be required to
         be provided."

3. Section 4.1 of the Plan is hereby amended by adding a new subsection (c) to
that Section immediately following subsection (b), to read as follows:

         "(c) Effective August 1, 2003, the Matching Limit shall be reduced from
         five percent of the Participant's Compensation to zero percent of the
         Participant's Compensation, and no further contributions shall be
         permitted to a Participant's Matched Before-Tax Contributions Account
         or to a Participant's Matched After-Tax Contributions Account.

         All deferral elections made by a Participant under Section 4.1(a) and
         in effect on July 31, 2003 shall be recharacterized as an election to
         make Unmatched Before-Tax Contributions under Section 4.2(a), and
         beginning August 1, 2003 such amounts shall be contributed to the
         Participant's Unmatched Before-Tax Contributions Account. All deferral
         elections made by a Participant under Section 4.1(b) and in effect on
         July 31, 2003 shall be recharacterized as an election to make Unmatched
         After-Tax Contributions under Section 4.2(b), and beginning August 1,
         2003 such amounts shall be contributed to the Participant's Unmatched
         After-Tax Contributions Account. A Participant may change or suspend
         his or her recharacterized contributions in accordance with the
         provisions of Section 4.4 and Committee rules."

4. Effective August 1, 2003, the Plan shall be amended by deleting the
provisions of Section 4.5 of the Plan. Section 4.5 of the Plan shall be reserved
for future use, as follows:

         "4.5  [Reserved]."

5. Effective August 1, 2003, the Plan shall be amended by adding a new Section
4.7A immediately following Section 4.7, such new section to read as follows:

         "4.7A  Discrimination Limits on Before-Tax Contributions

         (a) In General. For 2003, and prior to the beginning of each subsequent
         Plan Year, and at any other time during the Plan Year that the
         Committee may deem appropriate, the following test shall be made to
         prevent the Before-Tax Contributions under the Plan from becoming
         discriminatory. In accordance with the provisions of section 401(k)(3)
         of the Code and Treasury Regulation section 1.401(k)-1(b), the
         Committee shall gather Before-Tax Contribution elections and shall
         determine whether the average deferral percentage for the group of
         Eligible Employees who are Highly Compensated Employees exceeds that of
         all other Employees by more than (1) 1.25 times, or (2) 2 times, up to
         a maximum difference of 2 percent, whichever results in the greater
         percentage.

         Since this section applies Code section 401(k)(3) using the current
         year testing method, it may not be aggregated under Treasury
         Regulations with a plan that uses the prior year testing method for the
         same testing year.

         (b) Highly Compensated Employee. For purposes of subsection (a), an
         Employee will be considered to be a "Highly Compensated Employee" in
         the current Plan Year if he or she--

                (1) is a 5 percent Owner (as defined in Code section 416(i)(1))
                at any time in the current or preceding Plan Year; or

                (2) for the preceding Plan Year, had Compensation from the
                Employer and Affiliates in excess of $90,000 (as adjusted for
                changes in the cost of living).

         A former Employee will be treated as a highly compensated Employee if
         he was a highly compensated Employee at separation from service, or if
         he was a highly compensated Employee at any time after he attained age
         55.

         (c) Average Deferral Percentage. The "average deferral percentage" for
         each group of Employees for a Plan Year shall be the average of the
         percentages (after any adjustments required under section 4.7),
         calculated separately for each Employee in such group, of Compensation
         each Employee elected to have contributed to the Plan (and any other
         "qualified cash or deferred arrangement" as defined in Code section
         401(k)(2) sponsored by the Company or an Affiliate in which such
         Employee is eligible to participate) as a Before-Tax Contribution for
         the Plan Year, treating a failure to elect any such percentage as a
         zero.

         Any excess contributions for such Plan Year (and any income allocable
         thereto) shall be distributed to the Employees by the close of the Plan
         Year immediately following the Plan Year being tested. For this
         purpose, "excess contributions' shall mean the excess of the aggregate
         amount of deferrals actually made to the Plan on behalf of Highly
         Compensated Employees for such Plan Year, over the maximum amount of
         such contributions permitted under subsection (a) (determined by
         reducing contributions made on behalf of Highly Compensated Employees
         in order of the actual deferral percentages beginning with the highest
         of such percentages.)" Excess contributions shall be allocated to the
         Highly Compensated Employee with the largest amounts of employer
         contributions taken into account in calculating the non-discrimination
         test for the year in which the excess arose, beginning with the Highly
         Compensated Employee with the largest amount of such employer
         contributions and continuing in descending order until all the Excess
         Contributions have been allocated.

         (d) Reductions During Plan Year. If the Committee determines before the
         end of a Plan Year that the limitation of subsection (a) might not be
         satisfied, the Committee may reduce the future Before-Tax Contributions
         of the Highly Compensated Participants such that the amount of a Highly
         Compensated Participant's future Before-Tax Contributions does not
         exceed such contributions of any other Highly Compensated Participant,
         or to the extent permitted by law, in such other manner as the
         Committee may decide.

         (e) Nonelective Employer Contributions. If the Committee determines
         that the limitation of subsection (a) has been or may be exceeded, to
         the extent permitted by regulations of the Internal Revenue Service,
         the Employer may make a contribution on behalf of Non-Highly
         Compensated Employees to satisfy the limitation of subsection (a). Such
         contribution shall be fully and immediately vested and may not be
         withdrawn pursuant to section 7.2 or 7.3 (relating to in-service
         withdrawals)."

         IN WITNESS WHEREOF, the Sponsor has caused this instrument to be
executed on its behalf by its duly authorized officer as of the 30th day of
June, 2003.

                                                 PCS ADMINISTRATION (USA), INC.



                                                 By /s/ Barbara Jane Irwin
                                                    ---------------------------
                                                    Barbara Jane Irwin
                                                    Sr. VP of Administration