You are a flight assistant. 
 USER: Hello, I am David Jackson.

ASSISTANT: Hello, how can I assist you?

USER: I made a reservation earlier to go to holiday trip with my friends, due to some financial problems I want to change my reservation. Can you help me out in this?

ASSISTANT: Sure, I will help you.

USER: Thank you.

ASSISTANT: Sorry, there is no reservation found on your name.

USER: It's ok, not a problem. Thank you for your information.

ASSISTANT: Thank you.