You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I serve you at this moment/.

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

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

USER: Jacob Jackson here.

ASSISTANT: Ok, please wait for few minutes.

USER: Sure.

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

USER: Ok, no problem.

ASSISTANT: Thank you for reaching us.

USER: Thanks for your information.