If you want to remove the incorrect signature you need to resend it to everyone. If you don't mind having the bad signature on the document and just want to add the correct one, you can download your completed documents, start a new envelope and send it to the necessary recipient. The old signatures will still be visible on the new document but won't retain their DocuSign signature validation. You'll need to retain both completed version in case your documents are legally challenged later or for audti purposes. But you'll end up with a final document with everyone's signature on it correctly without having to resend it to multiple people.

Hope this helps.