Answer: This can be done using a script. The script should be writing as follows.
Me: (smiles) Good day sir/ma'am, you're welcome to ABC supermarket.
Customer: Thank you
Me: please sir/ma'am, do you mind if I ask you a few questions, so as to determine how to serve you better.
Customer: you can proceed.
Me: (smiles) Thank you sir/ma'am
Me: please sir/ma'am, have you shop in our super market before.
IF YES
Me: Thank you for choosing to be our customer, hope we've been serving you better.
(Pause to hear a response, if no response proceed)
Me: in appreciation of your patronage, we have a free bonus coupon for you. Which gives you the right to shop with bonuses.
(Hand over the coupon to the customer)
Me: Do have a nice day from here!
IF NO
Me: Thank you for choosing to patronize us today. We hope to see you again.
Me: In appreciation of your patronage we have a free membership card for you. Which gives you the right to shop as a member of this super market.
(Hand over the membership card to the customer)
Me: Do have a nice day from here.