You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I abet you today?

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

ASSISTANT: Sure, we are gleeful to help you.

USER: Thank you.

ASSISTANT: Can you please wait for a while, I will check with the  reservation list and revert to you.

USER: Sure.

ASSISTANT: Thank you for your time. We hardly tried to find your reservation but, no reservation has been found against your name.

USER: Ok, no problem. Thanks for your information.

ASSISTANT: Thank you for reaching us.