To reinstate WIP that has been included in a bill you will need to reverse the bill, this can be done by the below:
From the Main Menu go into the General Postings.
Select the option SIB and tick the Reversal box.
Click NEW.
Put the Matter number in and find the particular bill you want to reverse.
Select the bill in the grid and then change the date if required as this may default to the date of the bill or todays date (this is dependent on your setting).
Select the Floppy Disk Icon to save and then select POST.
If the bill has an allocation against it this will show as highlighted and you won't be able to select to reverse, this will probably have an allocation against eg TCO.
If that is the case then you will need to reverse the TCO posting following the above but select TCO.