To change a customer's membership on the Checkout screen, follow the steps below.
1. Tap Checkout.
2. Select the customer. Then, tap Shopping Cart to select the membership.
3. Tap Add Item.
4. Tap Membership.
5. Tap YES to change the membership.
6. Tap Change Membership.
7. Tap Select Membership to choose a new membership.
8. Select the new membership.
9. Tap Next at the bottom of the screen to continue.
10. Enter the credit card details below. Then, tap Save.
11. Tap Checkout after processing the payment.