looking for a tool to align vertices to a wall

I need to realign an edge loop of verts to the same space in an even line but not create or deleate any.

Example: I split a model in half but some verts for the corner are not even and I need to get them even again so when I made a clone I can easily splice them back together.

move the cursor to where you want the verts to line up with (Shift+S->Cursor to selection can be handy for this), press . to make everything work around the cursor (press , to go back later). Then select all the verts you want to line up, press S to scale, X/Y/Z for the direction to align them in, and scale to 0

But that just groups them all into a ball. I need them to remain at there relative postion but just to align exatly straight like if I had sliced the mesh in half with a normal slice tool.

that’s what pressing the X or Y or Z key does
if you go S, X, scale to 0, then it scales all the X values to zero but leaves the others untouched - so they line up in the same YZ plane.

sweet! thank you

Yes, that is very helpful! Thanks!