There are two ways to withdraw approvals from PO.
[A] Go to "Approvals" module (1), select "sent" tab (2), Click on the checkbox (3) for PO whole approval is to withdraw. And then click on the "Withdraw Approvals" button (4).
[B] The other way is to go to the "PO" from Transaction Module (1) for which you want to withdraw approval, Click on "Approval Actions" (2) and then select "withdraw Approval" (3).
[C] Once the approval is withdrawn, click on "Other Actions" and select "Edit" option.
[D] Once you make the desired changes in PO you can again send it for approvals.
Keywords: Withdraw approvals, amend PO