Can You Heat Soldered Pipes To Separate How Do You Separate Soldered Copper Pipe?

How do you separate soldered copper pipe? - can you heat soldered pipes to separate

I have welded some copper pipes in my irrigation system to be. I've got out there, so you can replace anti-reflux damaged by frost last winter. Is it just the heat pipe and they gone? Then I simply slide it back, if I replace the broken part? I am not a plumber, so any detailed help would be appreciated.

Thank you,
VA