Hey Keith,
Thanks for reaching out to us!
Unfortunately there isn’t a built-in way to resync all the events at a single time. If this happens to be a common issue for the events that feed into your site, you could try setting a schedule for deleting all the events and then re-importing them once a week.
I know it’s not the best solution, however it wouldn’t take long and would be a lot easier than checking each event individually.
I’m sorry I wasn’t able to give you a direct response here but hopefully it helps to get you pointed in the right direction.
Thanks!