I was wondering what would happen when rexler with his ability to flip face down damage face up targets Chewbacca, who flips face up damage cards face down.

Chewbacca flips face-up damage cards face-down when they're dealt to him.
If a pre-existing face-down damage card is flipped face-up, his pilot ability doesn't happen. (Exsamples: R2-D2 as a Crewman, or being the victim of a Saboteur).

Thanks , that's what we thought, but wanted a clarification on it just the same

So just to clarify. Rexler does work against Chewie?

Yes. The process would be:

1. Damage is dealt. The damage cards are face-down at this time, so Chewbacca can't do anything with them.

2. Rexlar spends his Focus to flip the cards face up. The cards aren't being dealt to Chewie, so he still can't do anything to them.

3. The now face-up cards resolve as normal.

Yes. The process would be:

1. Damage is dealt. The damage cards are face-down at this time, so Chewbacca can't do anything with them.

2. Rexlar spends his Focus to flip the cards face up. The cards aren't being dealt to Chewie, so he still can't do anything to them.

3. The now face-up cards resolve as normal.

Or, possibly:

1. Damage is dealt, including a critical damage which is dealt face up.

2. Chewie flips the face-up card down before it resolves

3. Rexlar spends his focus and flips the card back face up, along with any regular damage

4. The now face-up cards resolve as normal