Changing a Text Style

I set up a style for text with BOLD enabled and named the style "Title Text". Then I applied Title Text to several text boxes (hundreds, actually) in several different CDRs.

Later I changed the text attribute of Title Text from BOLD to NORMAL. I expected that when I opened an existing file the change to be automatically applied to all instances of Title Text in that file; however, it seems that is not the case. I have to locate each instance of Title Text and then reapply the style to it.

When I open an existing file, how can I can automatically apply the updated Title Text style to all instances of text to which that style has been previously applied?