Change orders can only be accommodated for Vendor Blankets in Gateway using the VB Revision Form. This Form will allow you to change the dollar amount, period of coverage, description, and account string.
If you have a budgetary change for standard purchases ("SBs"); this would be handled as a TOE or cancel the order and reissue a new order if the vendor hasn't fulfilled the order yet. These will be treated as TOEs.
If the supplier responds with an unavailability of an item, or a substitute item; these changes can either be made on the Receiving side of the order, or treated with a cancellation of the order and reissuing with the revised item(s).