Can I replace a document?
New signed versions; when you must sign again.
Yes. Go to Upload your signed document and upload the new signed version. Earlier versions are kept and fingerprinted; the live page points at what is current.
When you must sign again
If something material on the record changes in a way that needs a new instrument, for example details that the blank was printed from, the app will tell you a new signed document is required. Do not upload an old signature for new wording.
Amending vs confirming
The quarterly email asks you to confirm that nothing has changed. If something has changed, sign in and update properly instead of confirming the old document. See Quarterly confirmation.