authorise,
authorize,
clear,
pass grant authorization or clearance for; "Clear the manuscript for publication"; "The rock star never authorized this slanderous biography"
ratify,
sign be engaged by a written agreement; "He signed to play the casino on Dec. 18"; "The soprano signed to sing the new opera"
co-sign,
cosign sign jointly; "Husband and wife co-signed the lease"
probate establish the legal validity of (wills and other documents)
validate -
prove valid; show or confirm the validity of something
nullify,
invalidate take away the legal force of or render ineffective; "invalidate a contract"
validate -
make valid or confirm the validity of; "validate a ticket"
vitiate,
invalidate,
void take away the legal force of or render ineffective; "invalidate a contract"
modify,
alter,
change make less severe or harsh or extreme; "please modify this letter to make it more polite"; "he modified his views on same-gender marriage"
