Question

they returned to the hotel to change.
subject
predicate nominative
adverb

Explanation:

In the sentence "They returned to the hotel to change", "They" is the subject as it is the doer of the action (returning). A predicate nominative renames the subject and would be a noun/pronoun after a linking verb, but here "returned" is an action verb, so predicate nominative doesn't apply. An adverb modifies a verb, adjective, or other adverb, and "They" isn't an adverb. So the correct label for "They" is subject.

Answer:

subject