Okay, I admit it, I'm stupid. Here's my question. I'm new to MEP and learning ever so slowly. One great tool is the Air Terminal Device Tag that will show the characteristics of the device along with the connection size and air flow. My question is this: I've just learned I can change the "Mark" from CD to different things better reflecting whether it's a return register, slot diffuser, etc. The problem is I've got a drawing I'm working with that only has one letter, i.e. D-1 or D-2. I would like to convert this back to at least two letters like CD for ceiling diffuser, or RR for return register, etc. How do I do this? I'm working in AutoCAD MEP 2014 if that matters. Thanks for helping a stupid engineer out.