how do i clear a signature in adobe acrobat reader dc

[kellyer16136006]

When I am completing a contract I am signing it to lock it from changes on the customers end that it is being sent to. When the customer asks for changes to the contract up until recently I was able to clear the signature and make changes and resign the document. I am no longer being given that option to clear the signature to make changes. Please let me know what I can do to get that option back.