Replace Polyine Geometry With Another Polylines Geometry - Lisp?

[ceethreedee.com]

I am using Civil 3D and quite often we use polylines as targets/boundaries etc. Can be quite annoying if you want to change them. 

I am curious if it would be possible via lisp to maintain the same object handle of a polyline and but replace all of its geometry with another selected polyline. Anyone got anything they have currently written that might do that?

[J_Spurgeon]

Unfortunately they do not share any common attributes that associate them together.