You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I render you at this moment?

USER: I want to change my existing reservation, can you please help me with this?

ASSISTANT: Sure,may I know your good name please?

USER: Rebecca Lee here.

ASSISTANT: Ok, please wait for few minutes.

USER: Sure.

ASSISTANT: There is no existing reservation found on your name in our records.

USER: No problem, thanks for your information.

ASSISTANT: Thank you for reaching us.