Use the filter/ cointrap, typically located at the bottom corner of the machine behind an outer door. Unscrew the filter having first put down a towel to mop up any excess water which ‘will’ come out. If the drum is full of water the machine will need to be pulled out a bit and tilted back to ensure all the water does not end up on the floor or take the machine out of position and lower the drain hose at the back into a basin and gravity will allow the water to flow until empty. If theres a blockage visible such as a coin, sock or hair bobbin remove it and screw in the filter fully. Then turn the machine onto a drain or spin cycle to test if the pump is working freely again. If this doesnt solve it you may need a technician to repair.