@cvc8445, there are several tools that could be used to accomplish this. One factor in choosing the tool is what apps the source RTF text and the revised text will be used in.
For example, if you are using MS Word, then the Word VBA Find/Replace tool is an excellent candidate. It supports several special forms of find, including RegEx, and it can also find/replace formats easily.
So, if you can layout your complete workflow, including the apps you want to use, then perhaps we can be more helpful.