How to avoid defaulting the buyer in purchase requisition line for Blanket agreement source?

Hi,

When we create purchase requisition for the item which we have blanket agreement, its defaulting the Blanket Agreement`s buyer name as the suggested buyer name (The buyer who created the blanket agreement). We want to make it blank means it should not default any buyer or it should default the buyer the one given in the item master.

Please suggest how to do the same?

Regards,

Prabhu