Erasing part of line renderer

I'm trying add some paint like functions with line renderer. Basically I'm drawing lines on my texture. The problem is I can't add an eraser to erase part of the lines. I don't want the whole line to disappear. I Just want to have some erased parts on my lines when user uses the eraser with the mouse. Painting white is not an option for this task. I tried to use get pixels but no luck. Any help will be appreciated.