You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: I wanted to change my reservation due to my planned program me got postponed. Can you help me is there any chance to change my reservation.

ASSISTANT: Sure, may I know your name please?

USER: I am Helen Nelson.

ASSISTANT: Ok, please wait for a moment.

USER: Sure.

ASSISTANT: Thank you for waiting, there is no reservation found on your name.

USER: Ok, no issues. Thank you so much for your valuable information.

ASSISTANT: Thank you.