There are two ways I think can think of.

1. Add both outfits to your character and just hide the one you don't need. So lets say you want to do outfit A first, then you hide outfit B, render the animation from frame 1 to 44. When that is done, you hide outfit A and unhide outfit B and then you render Frame 45 to XXX and then you combine the two animations in a video editor.

2. Probably the way I would prefer doing it. Is to save or duplicate your project into two separate files so one for Outfit A containing that segment. And another containing outfit B. When you are done rendering outfit A you just open project Outfit B and render that as well. That way you avoid ruining or screwing up one animation part with another.

Regardless of which way you do it, I would strongly advice that you render your animations as image files rather than videos if you ain't already. So in case something goes wrong you can simply render those frames again instead of the whole animation, it can save you a lot of time.