To rotate a pipe symbol to face the other side of the pipe, go to
Ribbon: DM Plumbing->Pipe Symbols-> 
Flip Pipe Symbol
Pulldown Menu: DM Plumbing->Pipe Symbols->Flip Pipe Symbol
You will be prompted to identify the pipe symbol to be flipped.
Select pipe symbol to flip:
The pipe symbol will be flipped to face the other side of the pipe.
