Is there a way to create purchase requisition on behalf of requester out of the system

Hi community,

We have a business case where the requester of a purchase requisition demand do not exist in our system. Currently, the preparer must select a requester from a list of value. So we can't place a demand on behalf of that person if it is not previously define in our system.

Is there a way to by-pass that validation and let the preparer enter a name that is not in the list of value?

Thanks!

Etienne