Master Billing Run
If you have set up Parent- Child relationships for your customers, you will need a Master Billing Run to roll all the Child invoices to the Parent invoice, which will then be emailed out to the customer.
From [Billing Cycles>>Redo Master Bill]
Figure 1: Master Bill
From the Redo Master Bill screen, click on the Billing Run that you would like to have master bills created for.
Figure 2: Select the Billing Run id
If you want the billing to be run for only 1 or a few customers, click on the Customer drop down list and highlight only those customers that you want the Master bill to be run for. Then click Start.