You can create a Journal posting to the Debtors nominal (Client Ledger Office Side) but I would advise that this shouldn't be done as the matter listing reports would not balance back to the nominal if this was in balance at the point of the postings.
The Postings that are incorrectly posted should be corrected instead of a Journal.
To create a Journal, you can follow the below steps:
From the Main Menu go into the General Postings.
Select the Transaction Type J and then NEW.
Put in the first nominal and the details, also if you want to debit or credit the amount.
Select the Floppy Disk icon.
Create the opposite entry for the other nominal the journal is affecting.
Select the Floppy Disk icon again.
Select POST at the bottom of the screen.