Hello there, rlinton.
Currently, the option to change the time format isn't available in QuickBooks Online. Rest assured, I'll take note of this idea and share it with our developers. This suggestion will be analyzed by our Development team and may be added as one of QuickBooks Online new features.
I would also suggest checking out our blog, so you'll be updated with our new feature released.
You can also take a look at these articles to know more:
I'm always around if you still need my help!
