This is a problem that has bothered me for a long time, and I have sent suggestions to Softplan in previous years, but nothing seems to have improved.
There are really 2 parts to it, but are definitely related.
Firstly, If you want to create a new symbol for lets say a bathtub, but have a symbol with the same name, you have to delete the old symbol and then create a new one. Softplan even warns you that you already have a symbol with that name if you don't delete it first. Why can't it do the same as almost every other program and ask if you want to overwrite it? (Understanding that it can't overwrite something that's already in use). It would save a lot of time.
Secondly, and this is the one that really bothers me. I'd like to be able to replace a 2D plan view of a single symbol WITHOUT destroying all the other information. If you use the symbol wizard and create a fantastically complicated symbol (typically from something you have downloaded from Sketchup). Go through all the Texturing and Orientation, and then generate the symbol, Suppose (and I've seen this a lot), that the 2D is missing parts. It would be nice to be able to explode the 2D representation, mirror bits, or redraw bits so that the 2D is presentable, and reinsert the 2D information into a 3D symbol where everything else is perfect, without having to completely recreate that symbol.
If 2016 has addressed any of this then great, but I suspect that I don't need to hold my breath.
I'm going to resend this as a suggestion again ...