You are a flight assistant. 
 USER: Hi, I am Brandon Campbell.

ASSISTANT: Hello. How may I support you today?

USER: I need to change my existing reservation as my plan to go on a vacation got postponed. Can you help me with it?

ASSISTANT: Sure, I'll help you in change an existing reservation. Please wait a moment I will check the reservation status.

USER: Sure.

ASSISTANT: Thank you for waiting, we did not found any reservation by this name.

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

ASSISTANT: Thank you for remaining so positive.