You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Michael Anderson.

ASSISTANT: How can I assist you today?

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, I will wait for your response.

ASSISTANT: Sorry, no reservation is found under your name in our website.

USER: That's not a problem. Thank so much for your response.

ASSISTANT: My pleasure, have a great day.