You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Can you please help me in changing my existing reservation, as my health is not good?

ASSISTANT: Sure, can you share your name?

USER: Thank you for the response, my name is Brandon Walker.

ASSISTANT: Sorry, there is no reservation found under your name.

USER: Ok, not an issue. Anyways, thank you for the information.

ASSISTANT: Thank you for reaching us.