You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Stephen Young.

ASSISTANT: How may I assist you?

USER: I wanted to change my reservation due my planned program got postponed. Will you please help me?

ASSISTANT: OK, please wait a moment.

USER: Sure.

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

USER: Ok, it's fine. Thank you for your help.

ASSISTANT: Ok, thank you for contacting us.