Heya,
You just need to do a conversion.
Premiere Pro might do it automatically for you in the time-line – However, if for Cinema or other projection out, that is not a good way to do it. Reason being that the footage is not locked, so if you transfer project to another workstation, there is a risk that it won’t give you the exact same conversion in the time-line.
Instead, maybe check out what the Adobe Media Encoder will turn out for you.
As you are going from 24 fps to 30 fps (Although I suspect it is from 29.97 fps to 23.976 fps?), then there is a good chance that it will look much better, than if your went from 25 fps and down to 24 fps.
There is a whole science of pulling up and pull down of frame rates, and how you “remove” or “add” frames.
Makes sure to convert your .srt files to a codec that matches, and at the highest quality + also create a project, where the “old” 30 fps files are not present. Just so you don’t accidentally use them, and have to go back and find and replace those edits later.
Good Luck!
And, do let us know what worked for you.
Atb
Mads