You are a flight assistant. 
 USER: Hello, I am Dennis Jones.

ASSISTANT: Hello, how may I assist you?

USER: As my plan to go for shopping got postponed, I want you to change my reservation. Can you please help me?

ASSISTANT: Sure. Let me check the reservation list and revert you.

USER: Ok.

ASSISTANT: We have gone through the data base but could not find any reservation by the name you provided.

USER: It's ok, no problem. Thank you for the information.

ASSISTANT: Thank you for reaching us.