You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Donna Martinez here.

ASSISTANT: Donna, how may I aid you?

USER: I need to cancel my recent reservation because my trip dates are postponed.

ASSISTANT: Sure, please give me a moment to check your ticket status.

USER: Ok, take your own time.

ASSISTANT: Sorry, no reservation is available by your name.

USER: It's ok, thank you for checking.

ASSISTANT: Thank you for choosing us.