Close off the main valve. Open faucets below the pin hole leaks. Say a sillcock if no basement.
Open the faucet near the pin hole.
The object is to drain the water away and to release steam that would arise when you apply the heat to resolder. A compressor sometimes is helpful.
Not being able to see the pipe in question, I would unsolder, clean and flux again. I assume that your talking about a pin hole at a solder joint and that you may have spoiled that joint trying to do a repair. Not hard to do.