To change the payer on an existing billing schedule so that future charges are assigned to the new payer:
  1. Select Records, Students, and open the student's record
  2. Select the Activity tab, click the drop down menu for View, and select Scheduled Activity.
  3. Double click on the billing schedule to open it.
  4. Select the Apply To tab.
  5. For the original payer, change the Scheduled amount to $0.00
  6. On the first blank row, add the new payer's name
  7. Near the top of the Apply To tab, note the amount that appears for Remaining: and enter this amount in the Scheduled field on the new payer's row.
  8. Click Save and Close

    The new payer is now assigned to the ungenerated balance of the billing schedule.
For related information, refer to:
How to change the payer distribution on a charge (BB338114)
How to change a billing schedule in Student Billing 7 (BB269006)