Reshape Line Using Trace

How to use the trace tool in ArcMap to reshape a linear feature? The problem is that you cannot select both the feature to trace and the feature to reshape at the same time.

Use Map Topology. Set the feature class you are reshaping as the only fc participating in the map topology. Then select the feature you want to reshape with the topology selection tool (“topology edit tool”). Then use the “regular” select tool to select the feature you want to trace. Set the task to “reshape edge”. NOW you can use the trace tool as much or little as you like.

Thank you to Dan Seidnesticker for taking the time to ask about something which has troubled me but that I’ve never gotten up the gumption to ask, and Korine of York County for the solution (ESRI-L).