I have a team that's working with the Calendar App and we can't figure out how to have more than one person work on editing it. Is that possible? We don't need to transfer ownership, just have someone work on it...
Yes, you can have multiple people editing a Calendar App at the same time, however you will want to be careful about what changes you are making.
If users are unable to make edits, you may want to check their sharing permissions on the source sheet, as they would need Editor or higher permissions (see here for more details!)
Should this not resolve your issue, I would suggest reaching out to Smartsheet Support with additional information (such as the email addresses shared, screen captures of the calendar, the calendar configuration, any error messages they are receiving, and the name of the source sheet, etc).
I am having the same issue as well..my co-workers are listed as ADMIN for the parent sheet but cannot edit the Calendar App at all. Could this because they do not have the same license as I do?