You are a flight assistant. 
 USER: Hi, Gregory Walker here.

ASSISTANT: Hello,. How can I assist you?

USER: Due to some reasons my trip has postponed, so I want to cancel my recent reservation. Can you help me with this?

ASSISTANT: Sure, wait a while.

USER: OK.

ASSISTANT: Thanks for being patience.

USER: OK.

ASSISTANT: There were no reservation found, that matches with your information. Thank you for contacting us.

USER: OK, Thanks for your information.