You are a flight assistant. 
 USER: Hello, I am Ashley Walker.

ASSISTANT: Hello, How can I assist you?

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

ASSISTANT: Sure, please wait a moment, I will check and get back to you.

USER: Ok, I will wait.

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

USER: Ok, no problem. Thanks for your service.

ASSISTANT: Thanks for choosing us and have a great day.