straighten out vs modify

straighten out and modify both are verbs.

Word	Noun	Adjective	Verb	Adverb
straighten out	No	No	Yes	No
modify	No	No	Yes	No

As verbs, modify is a hypernym of straighten out; that is, modify is a word with a broader meaning than straighten out:

Other hypernyms of straighten out include alter, change.

straighten out (verb)	modify (verb)
put (things or places) in order	make less severe or harsh or extreme
settle or put right	add a modifier to a constituent
change for the better	cause to change; make different; cause a transformation
make free from confusion or ambiguity; make clear
make straight
extricate from entanglement