You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: My client meeting has been postponed, so I want to reschedule my itinerary dates.

ASSISTANT: Can I know your name?

USER: Sarah Johnson here.

ASSISTANT: Ok. Let me check details with your recent reservation.

USER: Sure.

ASSISTANT: I regret there is no reservation by name Sarah Johnson.

USER: No problem, thank you.

ASSISTANT: Thank you.