Firstly I would not recommend editing the Wiring Design XML - that could cause problems downstream. I think you should raise an SR and talk with someone in Support, they can advise and understand what you are trying to achieve (perhaps they can show how "Find and Replace" can be used to select / swap a symbol used in the Wiring design for all matching instances in a design).
Yes I forgot I can make use of the Find and Replace tool for swapping symbols.
Thank you Nuri, I was trying to replace symbols the hard way
Now the trick will be finding a symbol that was removed from the symbol library.