Keep in mind the following when using the Undo Split Billing program:

Only work-in-process transactions are affected by the Undo Split Billing program. If you need to undo a split that has already been final billed and updated, you will first need to undo the corresponding updated statements for split matters associated with the main client. Once the corresponding statements for all matters associated with the split have been undone, you can then undo the split billing.
If the Undo Split Billing program is run after the split matters have been final billed (but before their statements are updated), then final statements must be run again for the associated split matters before they can be updated.
Transactions split prior to Version 17 cannot be reversed using the Undo Split Billing program. If you ant to reverse split billing that was adjusted prior to Version 17, you can write-up or write-down the affected matters to the original billable amounts from before the adjustment. However, due to rounding, the amounts may not be exactly the same as they were before the adjustment.
If the Undo Split Billing program is run after the split transactions have been deleted, it will still restore the original transaction or transactions to the main client.
See also:   Split Billing Overview
  Perform Split Billing