How do I undo this?

[tookie]

hi all. I had a diverter valve put in for some reason and now want to use it again. but the plumber put something in it. I don't know how to get that out and use it again.

I want to put a counter top water filter in but this thing is clogged seemingly permanently.

thanks for any help

 

[Mr_David]

The little gray piece on the blue tube Push it into the fitting and hold it in with something and then just pull the blue tube and cap fitting out. Then all you have to do is push a new piece of tube into the fitting.