You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Christopher Nelson here.

ASSISTANT: How can I help you?

USER: Can you please help me in changing my recent reservation? As my planned trip has been postponed to some other dates.

ASSISTANT: Sure, I will help you with this. Please be on hold for a moment.

USER: Sure.

ASSISTANT: Christopher Nelson, there is no active reservation found under your name in our database.

USER: That's ok, thank you for giving the information.

ASSISTANT: Thank you for contacting us.