Once you have already put a deposit onto your client's account, you can then use it to pay for treatments when the time comes.

1.  Once that client has an appointment in the diary you can check them out as normal. 
2. You will notice the system will alert you that the client has a deposit on account:
   
   
   
3. Press Ok and continue to press Pay.
4. Press the calculator next to Account and enter in how much of the deposit you wish to use
   
   
   
   
5. The system will now tell you hos much is left to pay. You can use the calculator again on another payment type to enter in the remaining balance.
   
   
   
6. Press pay.

This will then have zeroed off the clients account and no longer have a deposit. 

This will also appear on your financial statements as "Account". But this does not affect your takings in any way.