Are you using the "Play" action or "Play (by name)" action?
If you're using "Play (by name)" then you could just change the name of the the new sound (in the project folder) to whatever name you're currently using in events.
If you're using "Play", then I believe you are out of luck. You'll have to change each one individually. If that's the case you can at least use the Find function (ctrl + f) to get a big list of them and then double click on each of them in the Find Results window to jump to it.