How can I remove the part of the object that is inside the (hollow)cylinder? How can I remove the part of the object on the right that is inside the cylinder?

I also want to remove the part that sticks out:



How can I do that?

EDIT:
New screenshots to show the objects:
I'm not sure you've made a good topology but anyway if I've correctly understood what you want and if I wanted to do it quickly I would use the Knife tool