prompt on the CDS

have it ask:

Are you a loyalty member or would you like to join?" and have a yes/no option. 

If a customer selects yes, she would like the system to open the keypad for customers to enter phone number for Loyalty to either sign in, or create a loyalty account. If the customer selects no, the system closes the prompt on the CDS and the cashier would ask for and enter a customers name.