answer: #Person2# helps #Person1# apply for an immigrant visa for Family Reunification.
documents: #Person1#: Excuse me. I'd like to apply for an immigrant visa.
  #Person2#: Under which category do you intend to apply?
  #Person1#: Oh, my son is an American citizen. We want to live together in the future.
  #Person2#: So that's the Family Reunification.