Phillip944 wrote:
The problem is that I heated the old elbow, but nothing happened. I
heated the pipe & the elbow... nothing. Couldn't get it off.

What are you using to heat the joint with? You'll need a propane torch
at a minimum.

Assuming you've got the right tool, it sounds like you've still got
water in the line. You'll need to drain it / blow it out with air in
order to heat the joint adequately to remove the elbow.