You are a flight assistant. 
 USER: Hello. I am Samuel Harris.

ASSISTANT: Hello. How can I help you?

USER: Due to my health problem I want to change my reservation, can you please help me that?

ASSISTANT: Sure. Please, wait for a while.

USER: Ok.

ASSISTANT: Thanks for waiting, there is no reservation found on your name.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for choosing us.