unsign

verb2

1. •
   To remove one's signature from (something one has signed).

   • UNSIGNING AND CHANGING A REPORT SHOULD ONLY BE USED IN VERY RARE CASES IN WHICH FAILURE TO CHANGE THE ORIGINAL REPORT COULD RESULT IN SIGNIFICANT HARM TO THE PATIENT. — 2010
2. •
   To declare void one's signing of (a treaty).

   • Third, transnational legal process could be used to erode the force of the novel US tactic of unsigning the Rome Treaty. — 2005