You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I give assistance to you?

USER: I am Christine Smith. Due to some health issue, I want to change my existing reservation. Can you please help me with this?

ASSISTANT: Sure, please wait for a while.

USER: Ok, I will wait.

ASSISTANT: Thanks for your time, there was no reservation found on your name to change it.

USER: Ok, Thank you for your service.

ASSISTANT: Thank you for approaching us.