The Edit Multiple Cable Trays command is used to edit multiple individual cable trays sections. The selected cable trays do not need to be connected to each other. You do not need to select all of the cable trays in a branch.
To edit multiple cable trays, go to
Ribbon: DM Electrical->3D-BIM-> 
Edit Multiple Cable Trays
Pulldown Menu: DM Electrical->Cable Tray->Edit Multiple Cable Trays
You will be prompted to select the cable trays to be edited.
Select cable trays to edit:
The Edit Multiple Cable Trays dialog box will appear.
Edit Multiple Cable Trays Dialog Box
Changes can be made to the cable trays in the same way as when they were inserted. See the Insert Cable Tray section for more information.