Hi Dale,
The Q2 system typically does not allow for customers to be migrated if they have pending transactions as a general rule, therefore the Group Mover endpoint doesn't provide the ability to override this. However, you can move the other customers within that bucket that do not have pending transactions by setting the OmitPending flag to true.
The flag was provided to override the previous behavior with the Group Mover endpoint, where the entire batch or bucket of customers from the migration would fail if one of them had pending transactions. Setting OmitPending to true would simply allow for all of the "valid" customers to be migrated and skip the ones with pending transactions.
Solène