。
She had the porter carry her heavy suitcase.
Literal
She [topic-は] heavy suitcase [object-を] porter [to-に] carried [for her-てもらった].
~てもらう (to receive the favor of someone doing something) is the counterpart to ~てくれる, but seen from the receiver's perspective with an active nuance — she arranged for the porter to carry it. The に marks the person who performs the service. This is part of the giving/receiving verb system (授受表現) that encodes who benefits and who acts in Japanese social interactions.