If the date needs to be changed while the request is in pending status, there is no way to change it without deleting the entire request and re-adding it. Being able to change the date instead is more efficient.
I think a lot of these issues must be credential based. I can open an event from the pending requests by clicking on the magnifying glass, scroll to the bottom and choose "edit event", make changes then choose appropriate save button at the bottom. Or if you want to change a number of recurring events, go to all occurrences, choose which events, click on edit events at the top, do your edits and save.
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