Thank you, thank you, thank you, thank you Pete340!!!!!!
After hours of searching (well ok, an hour of searching), your post has been the only one that has made sense on how to do a search and replace with regex. As a designer, most of the answers on stackoverflow etc. just doesn't make sense, but yours finally let me change tags while leaving content. Brilliant!
And for anyone else searching, the way to change/replace tags while leaving the content is:
Original: my content here
Find what: (.*)
Equals: my content here