regex replace

I want to make a program which will look for a expression <disp-formula id="deqn(\d+)-(\d+)"> in files and if there is one or more match, then it will search the whole file for expressions in the form <xref ref-type="disp-formula" rid="deqnX">(X)</xref> or <xref ref-type="disp-formula"...

I'm trying to figure out how to change a trailing character using Regex Replace. I have a text field for last name that I'm trying to standardize using Regex. I'd like to change the trailing character from lowercase to uppercase every time an apostrophe occurs (ie: O'connor should be O'Connor)...