You are a flight assistant. 
 USER: Hello. Myself Ronald Smith.

ASSISTANT: Hello, how may I serve you at this moment?

USER: I want to change my existing reservation, can you help me in that?

ASSISTANT: Sure, please wait for few minutes.

USER: Thank you. I will wait for your response.

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

USER: That's ok, no problem. Thank you for waiting.

ASSISTANT: Thank you for reaching us.

USER: Thank you for the information.