reassignment vs duty assignment

reassignment and duty assignment both are nouns.

Word	Noun	Adjective	Verb	Adverb
reassignment	Yes	No	No	No
duty assignment	Yes	No	No	No

As nouns, duty assignment is a hypernym of reassignment; that is, duty assignment is a word with a broader meaning than reassignment:

reassignment: assignment to a different duty
duty assignment: a duty that you are assigned to perform (especially in the armed forces)

Other hypernyms of reassignment include assignment.

reassignment (noun)	duty assignment (noun)
assignment to a different duty	a duty that you are assigned to perform (especially in the armed forces)