How to get an oval shaped copper pipe round again to installcompression fitting
 

Hi,

The old main valve of my house doesn't stop the water flow very
tightly when shut off. I need to install a new main valve. It's on
3/4" copper pipe. I'll install the new valve just over the old one.
The problem is that the old pipe is now more oval in shape than round
and I'm afraid that the joint will leak. I planned to use a
compression fitting, since the old valve, when closed, lets pass
enough water to prevent us using soldering.

Is there a way to get the pipe round again?

Best regards,
NeilSanner