I will go to the Philippines and pass Krabi on the way. I would like to change Thai Baht to USD. Please confirm that it would be easy in one of the banks or the exchange shops. Just to be shure before travelling.

Doubt whether you can exchange over the counter at the Krabi banks. Usually you have to order foreign currency and have to wait a few days. But you can change baht to foreign currencies at most international airport terminal exchange booths.