vitiate -
corrupt morally or by intemperance or sensuality; "debauch the young people with wine and women"; "Socrates was accused of corrupting young men"; "Do school counselors subvert young children?"; "corrupt the morals"
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"
validate make valid or confirm the validity of; "validate a ticket"
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"