Not sure I like this one, but here goes. Lets say you have multiple polylines that you need to change into polylines and you don't want to go through each one at a time. Use the undocumented DebugAlignment. Type it into the command line and then select the polylines you want converted, I think it uses the settings in the toolspace settings commands CreateAlignmentEntities when converting them. Once you do this you need to go back and name the alignments. It is pretty easy if you rename them from the Prospector and selecting the Alignments in the Site and changing them in the adjacent window.