To get there, go to Transactions->Purchasing->Purchase Order Entry. Click the Actions button and pick Create and Copy New PO. A window will pop up asking for the source P.O. and then you get to tailor the new P.O. that gets created. You can set the Vendor, Currency, Customer, Dates, Sites and Cost options.
Also you can optionally:
- Copy all P.O. lines
- Include cancelled lines
- Include cancelled quantities
- Display the new PO when done
- Copy freight, miscellaneous or shipping amounts from the original
- Copy Ship to Address, method and Tax ID from the source PO