When completing a goods in for an order the system will automatically ask you if you would like to book the part out to the customer. As shown below:
If you select Yes the system will automatically divert you to the parts point of sale screen to complete the transaction.
If you select No you can book the part out at a later date.
To do this, sell the part out as normal on the parts point of sale screen. If the part is being sold to a customer who has previously paid a deposit for this part, when invoicing the system will automatically register this.
The system will generate an invoice showing a credit for the deposit and balance for the actual part automatically. Please Note: That this will not reflect on screen. This only generated when the invoice has been raised.