You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I hep you?

USER: Actually, I made a earlier reservation to go for a trip with my friends, but heavy work load in office. I want to change my reservation. Can you help me in this?

ASSISTANT: Let me know your name?

USER: Myself David Adams.

ASSISTANT: Sorry, no reservation found by your name.

USER: It's ok, thank you.

ASSISTANT: Thank you.