Select everything not inside quotations

[busy_sample]

Hi, thanks for having this forum. I have a rather long document with a lot of dialogue. I would like to change it from present tense to past tense. I know I can find and replace words like 'is' with 'was' and change word tense, but I don't want that to happen inside the dialogue. (It makes it pretty much gibberish)

Is there a way to select what's not inside dialogue, then change the tense?

Any help is appreciated. Thank you!