Client may, at any time, make changes in, additions to or deletions from the scope of the Work to be performed pursuant to the Contract (an "Amendment"). If any such Amendment increases or decreases the time required for the performance of Contractor's obligations or increases or decreases Contractor's cost of performing the Work, an equitable adjustment shall be made in the date or dates in Appendix B or Price, or both using so far as practicable any pricing information or rates set out in Appendices C and D; provided, however, that Contractor shall not be entitled to any advance payment on any increase in the Price as a result of any Amendment. The prior written consent of the Client shall be required before any Amendment is put into effect.