To modify a pipe symbol that is inserted on the drawing, go to
Ribbon: DM Plumbing->Pipe Symbols-> 
Query Pipe Symbol
Pulldown Menu: DM Plumbing->Pipe Symbols->Query Pipe Symbol
Select the pipe on the drawing to be queried.
Query Pipe Symbol Dialog Box
Changes can be made to the pipe symbol in the same way as when it was inserted. See the Insert Pipe Symbol section for more information.