Auto reformatting a script within Scrivener

Hey

Sure that what I’m after is easy to do and I’m an idiot for not finding a solution myself but basically:

Have a script in a certain custom format, decided I want to change the format and have these changes apply to all of the script elements (dialogue, character, scene action etc)

How can I do this? Currently when I change the script settings, everything stays the same it’s only the new elements which change, how can I apply these changes to the old?

Know some basic XML and such if that’s a workout.