You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I serve you today?

USER: I want to change my reservation as my plan to go for shopping got postponed. Can you help me in changing my reservation made on name Donald Baker?

ASSISTANT: Sure, wait a moment I will check the reservation list.

USER: Ok.

ASSISTANT: Thanks for waiting, we did not found any reservation active in our database.

USER: That's Ok, thanks for your response.

ASSISTANT: You're welcome. We're glad to serve you again.