G.♣.
Potty training and vacations rarely mix. The more you are able to stay around the house in the beginning, the easier it is for kids to get used to the new routine.
I remember my son asking for a diaper when he needed to poop. I told him that we were done with diapers and he needed to poop in the potty. He did not like hearing that at all, and I really second guessed myself. But I stayed calm, and he tried the potty.
If you want to wait him out, you can. He really will decide on his own that he's ready to poop in the potty. It might take awhile, but it will happen.
If you'd like to speed things along a bit, it's time to take away the diapers. Let him know that you are going to do that. "Bobby, today is the last day for diapers. Tomorrow you will poop in the potty." Stay calm, and don't get emotional about it. Just be matter-of-fact. If you are concerned that he will hold it in and be constipated, you could try giving him lots and lots fluids and feed him foods that are high in fiber.
Honestly, I spent a few days saying, "Poop goes in the potty."