modify

(verb) make less severe or harsh or extreme. Examples: "Please modify this letter to make it more polite." "He modified his views on same-gender marriage."

(verb) add a modifier to a constituent. Synonyms: qualify.

(verb) cause to change; make different; cause a transformation. Synonyms: change, alter. Examples: "The advent of the automobile may have altered the growth pattern of the city." "The discussion has changed my thinking about the issue."