Proposed changes in the goods subject to this Contract submitted in writing by the Purchaser will be reviewed by Seller for acceptability and for the effect of the proposed changes on shipping schedules and prices Seller will submit to Purchaser its decision to accept or not to accept the proposed changes and the amendments to the shipping schedules selling prices and other terms upon which the proposed changes would be acceptable to Seller the changes will become effective as amendments to this Contract upon Purchasers written acceptance of the said amended terms.