There is nothing worse than a full bowl of water left in your toilet but what is causing it? The title statement is a total misnomer and the flush does not affect whether the bowl empties or not. If you are left with lots of water in the bowl then there is an issue with your outlet or toilet waste. In other words the toilet is blocked so would need rodding or plunging to dislodge the blockage. If your bowl is full and you need to empty it them you can do this with a cup, bowl or sponge depending how bad it is, but on no accounts try and flush again. This will just put more water into the bowl and possibly overflow the toilet.
The correct statement should actually read how to drain a cistern when the flush is not working!
This is required when you need to do some repairs on the flush valve/siphon or the ball valve/fill valve. The best way to drain the cistern is to either isolate the fill valve by using the shut off valve that should be located under the cistern or failing this and the fill valve is not the issue you can fix the ball or float up so it does not operate. This is not ideal and should be a last resort, failing that turn the water off. Once you have stopped more water flowing into the cistern you can then flush the tank to empty it. If the lever or button is not working you will have to manually open the flap in the siphon or flush valve. This will dump the water into the bowl and allow you to carry out necessary repairs. Please check out our videos for the best practices. There may be an amount of water left in the cistern and a large sponge is ideal to soak up the water and make it as dry as possible.
Once you have got rid of all the water then you can do the necessary repairs.
The bowl water and the water in the cistern never come into contact with each other for hygiene reasons and if you are getting this occurring you have a major fault.
Good luck and always watch FlushKING TV to get the right answer.