Hold possible duplicate invoices, link repeat quotes, check purchase forms. Every one is ready to run, and you can adjust it in plain language.
Keep supplier quote updates visible on requests awaiting approval.
Your approver sees the supplier's new quote on the original purchase request, with a link back to the buyer's task.
Put overdue supplier edit requests in the owner's task list.
Your procurement owner gets a clear task to resolve supplier edits that hold up an overdue signature.