I’d just add an edge loop (ctrl-r) and slide it to where I need it. If you need to change it later on you can reposition it with hitting g twice.
edit - in case you mean to keep the curvature, that’s a good one, not sure if there’s a one click solution for that. This addon is quite handy though for situations like these - It is finally here... EDGE FLOW (SET FLOW) for Blender ! (Benjamin Saunder)