You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how can I assist you?

USER: I want to alter my existing reservation, because my friends are not able to come on those dates which we planned earlier. Please help me in changing?

ASSISTANT: Sure, I will help you. To proceed further, May I know your name?

USER: Sure, I made a reservation on the name of Jessica Jackson.

ASSISTANT: Ok, please wait a moment. I will check the reservation list and revert to you.

USER: Ok, take your time.

ASSISTANT: Thanks for waiting, I have checked all the reservation list but I could not find any reservation on your name.

USER: Ok, no worries at all. Thank you for your kind service.

ASSISTANT: Thank you for choosing us.