Answer: countersign

AnswerCrossword Clue
COUNTERSIGNAssume liability for, as another's loan
COUNTERSIGNSentry's demand
COUNTERSIGNConfirm in writing
COUNTERSIGNDeli menu?
countersignto sign with a signature attesting the authenticity of a document already signed by another
countersignAdd a signature to (a document already signed by another person)