You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Charles Martin.

ASSISTANT: How can I assist you today?

USER: I had planned to go on a trip, but it was postponed due to some reasons. Can you change my recent reservation?

ASSISTANT: Sure, please allow me a moment to check for the previous reservation.

USER: Ok, take your time.

ASSISTANT: Charles, there is no reservation found under your name.

USER: That's ok. Anyways, thank you for your help.

ASSISTANT: Thank you for contacting us.