Not sure what software you are using but I would guess Vectric...select the toolpath, and then the "delete toolpath" icon below.

To change the line the toolpath is going to cut, you have to open the toolpath and select the new line you want to use on the 2d drawing.
Then re-calculate the toolpath.

I usually include the depth of cut in the toolpath name, such as 060 is a cut 6/100th deep, be careful using too many decimals in a Vectric toolpath name.