Terminate Assignment done as a Correction

Does anyone know if there is a way to correct the following situation?

A non primary assignment was active for 9 months and then should have been terminated.  When the assignment was changed to Terminate Assignment, it was done as a Correction.  So the assignment was paid for 9 months but shows as never having been active.  

Is there any way to reverse this transaction to keep a record of this assignment having been active for the 9 months before it should be Update to Terminate Assignment?

Thanks!