You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you out?

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

ASSISTANT: Sure, I will help you in changing the reservation. Can you please help me with the name you reserved?

USER: Thomas Jackson here.

ASSISTANT: Sorry, there are no reservations found.

USER: Ok, no problem.

ASSISTANT: Thank you for reaching us.

USER: Thanks for your information.