It should also be clarified...when they say you can only have two, they're talking about primary trade skills. Fishing, Cooking and First-Aid are secondary and you can have all three as well as the two primaries.
I've seen this a number of times. People pick-up one or two of the secondaries and think they're stuck with just those two.
You won't see an option to cancel Fishing, Cooking or First-Aid, as there really is no reason to.