Doc Date displayed on PO is not correct.
Purchase order was created on 28-Sep but while creating purchase order wrongly enter date as 29-Sep.This PO was created yesterday with today's date.
PO dated is printing date before. On Sept 28th, the PO printed Sept 29th.
It is possible to change Purchase order document date.
Once Purchase Order is Saved you cannot Change the Document date, Document type & Vendor Etc Fields.
You have to cancel that Purchase order and make a new Purchase order.