Calling a state requires an official graphic and/or statement by an anchor/caster. If it is immediately corrected as a clerical error, then it doesn't count. Otherwise, if 30 minutes pass after the last state is called without a correction, then that state resolves Yes.
For this market, Washington, D.C. counts as a state, and Nebraska and Maine are each counted as single entities, where the call is only complete once both the overall state and any separate electoral districts are called.
If CNN doesn't call one or more outstanding states long after they call the overall election (like if three weeks go by and they decide it would be strange to have an announcement), then whatever the last state they DID call will resolve Yes. This is unlikely; networks like having a complete record.
Feel free to add likely contenders, I've just started us off with 10 of the more contested or slow-counting states.