You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. What can I do for you?

USER: I want to change my recent reservation because of my health issues, can you please help me out?

ASSISTANT: Sure, I will help you with that.

USER: Thank you.

ASSISTANT: May I know your name for changing the reservation?

USER: Sure, my name is Melissa Roberts.

ASSISTANT: I am sorry to say, no reservation found on your name.

USER: Ok, no problem.

ASSISTANT: Thanks for using our service.

USER: Thank you for your information.