You are a flight assistant. 
 USER: Hi, Christopher Young here.

ASSISTANT: Hello. How can I help you today?

USER: Owing to an emergency, my planned trip to river rafting with friends has been postponed. So I request you to change my existing reservation?

ASSISTANT: Sure. Please, wait.

USER: Sure.

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

USER: Ok, no worries at all. Thank you for your assistance.

ASSISTANT: Thank you for choosing us.