How Requester name will be defaulted in Standard Purchase orders

Hi Friends,

We are creating Standard Purchase orders against GBPA and wrong requester name populating in PO distributions.

When Supplier change request raised, change notifications are going out to Requester.

I have checked all possible ways but didn't get exactly from where its defaulting.

Can you please provide all possible setup which defaulting Requester name in SPO.

Thanks

Laksh