Trying to change cartridge in single handle tub/shower

[Gui13]

Hi everyone,
Homeowner in distress here. I have two questions:

1. I am trying to remove the cartridge that is stuck in the handle (see picture). How can I remove it without breaking it?
2. How can I find a new handle that would be compatible with this particular type of cartridge? I am trying to keep the valve and cartridge of my existing installation, and just update the trim to a new style/color.

Many thanks in advance for your help!

Will

 

[Plumber69]

the finger shaped part of handle might unscrew and might be allen key

 

[Sponsor]

 

[MWr]

Take it all to the plumbing store, if you find one that works even now, they will definitely help you with all your questions.

 

[Gui13]

Thanks, I managed to separate the cartridge from the handle by following Plumber69's directions. Now, how can I find now a new handle that would fit this particular type of cartridge? I think the number inside the handle says 258620S.

Thanks again for your help!