I have tried to change the trade a litte after we agreed - always in mind that we already had a deal in the first place that I would gladly accept if we didn't agree on anything else, of course. But now that one of her troop-members needs it she backs out of the trade.
Watch Chanco21's water team vs. PHKES5's water team.
Chanco21 has a 1251 PvP rating and his team features 2 invincible, 1 counter, 1 shield, and 1 swap for actives.
This video explains how to properly use the Swap ability on Battle Camp. It also describes a method you can use to become better at it. All mechanics and calculations behind Battle Camp gem-matching are explained.
Backed out of trade after 24h.