You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I support you today?

USER: I am Elizabeth Martinez. I need to change my existing reservation, Can you please help me with that?

ASSISTANT: Sure, please wait for a while.

USER: Sure.

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

USER: Ok, no problem.

ASSISTANT: Thank you for choosing us.

USER: Thanks for your information.