You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Rebecca Thomas.

ASSISTANT: How can I oblige you today?

USER: Owing to an emergency, I want to change an existing reservation, so please help me in changing the reservation.

ASSISTANT: Sure, please wait for a moment.

USER: Sure.

ASSISTANT: Thank you for your waiting, there is no reservation found with the given name.

USER: Not an issue. Thank you.

ASSISTANT: Thank you.