Läser igenom och hittade denna blurb på YS 106:
The procedure to invoke an aspect that isn't on your character is precisely the same as a regular invocation: just declare how that aspect is relevant, spend a fate point, and take a +2 or a reroll. The only thing to keep in mind is that, if you're invoking an aspect on another PC or on a NPC to gain an advantage over them, that character will receive the fate point you spent, either at the end of the exchange (in conflict, see page 197) or at the end of the scene (outside of conflict).