If there is an error with leave calculations or you need to manually adjust leave for an employee, leave can be added from the Employee Master details screen.

The context menu provides leave transactions to be entered manually using the Add option. 

Employee Master Details > Leave icon > context menu > Add > Leave Journal Input

Leave is shown as negative hours, i.e. as a credit (the firm owes the employee the leave), so when adding more leave, you enter the transaction type as a C and the hours as a negative.  Where you are taking leave from the employee, you enter the leave transaction as T and hours as a positive. 

The Balance Days is calculated as Hours divided by number of hours paid per day (as entered on the Pay Details tab for the employee).  It is always best to look at Balance Hours rather than Balance Days.