The first thing you need to do when you find out that your swimming pool pump is frozen is to make sure that you unplug the electrical cord from the outlet. You do not want the pump to turn on while it is frozen because that could damage the electric motor or even burn it out. The next thing you will have to do is remove the pump from the filter system plumbing but you will need to first take a look to see if you have unions in your plumbing. If you do in fact have unions in your plumbing you will want to loosen to loosen the union collars and then remove the pump from the filter system plumbing.
If you do not have unions in the swimming pool filter system plumbing you will now have to pick from one of two choices.If you do not have unions on your swimming pool filter system plumbing you will either have to cut the pipe with a PVC saw or you will have to remove some of the plumbing where there is a union, meaning that there could be a union at the multi-port, so if you loosen that union the pump may separate with the multi-port. Also remember that if you decide to cut the suction and the discharge lines you can now install unions in the plumbing when you go to re-install the pool pump.
Now that you have removed the pool pump you will want to bring it indoors where the temperature is above freezing so that the ice that is inside of the volute and the pump impeller will thaw. After you have placed the pump indoors you will want to let it sit until all the ice inside is totally thawed out. There could be a chance that your pump housing is cracked so when you bring the pump inside you should make sure to place the pump over something that is able to catch the water inside. If you have a slop sink or laundry sink you could set the pump inside that until it has thawed. You will only need to worry about water leaking out of the pump if the pump has been cracked from the ice, but it is always a good idea to have something underneath the pump just in-case water does drain out.
Once you have let the pump sit for a while you can check to see if the water is still inside. If your pump is full of water now that it is not frozen anymore and its not leaking you will be ready to install the pump back into the system when the weather outside is steady above freezing. If all of the water has leaked out of your pump you may need to find out what has cracked and then replace the part. The most common part that will crack from the ice is the pump volute which is also known as the pump housing. If the pump housing is cracked you can either expoxy it back together or buy a new one and replace the existing damaged pump housing.