Withdraw email approval is the first action that should be taken to make the edits. Withdraw email approval is a feature that allows you to revoke the approval status of an email and make changes to it. You can use this feature if you need to update an approved email before sending it or sharing it with other business units.
Unshare the email is not necessary if you want to make edits to the email, and it may affect the access of other business units. Cancel send using email is not relevant if you have not scheduled or sent the email yet.