Thanks for joining this thread, P46.
I'm happy to provide some info about reassigning classes in QuickBooks Online.
While there are many options for customization in QBO, there currently isn't a way to assign classes to multiple transactions at once. This would need to be done individually. I recommend submitting feedback for the Product Development Team to review for future updates. This can be done directly through your account by clicking the Gear icon then Feedback.
In the meantime, I'm linking a couple of articles about classes you may find helpful:
Please feel free to reach back out if you have any other questions. I'll be here to lend a hand.
