Technically speaking Check-Ins can be deleted. However, if you choose to delete, it will delete all of the Check-In records associated with that employee. Individual Check-In responses cannot be deleted.

This prevents users from deleting data that could easily slip through the cracks. If someone has 100 Check-Ins, we would not want someone to simply "erase" the data in a Check-In that was not favorable.

Have a duplicate Check-In?

No problem. The employee will only see one Check-In at time and can only respond to the most recent Check-In questions. Your manager can simply ignore the duplicate and only needs to respond to one of the Check-Ins. The system will not be affected by having additional records.