You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello, how may I serve you today?

USER: Owing to an emergency, I need to change my existing reservation.

ASSISTANT: May I know the name?

USER: I am Donald Thompson.

ASSISTANT: Ok, please wait.

USER: Sure.

ASSISTANT: Sorry, there is no reservation found on your give name in our database.

USER: Thanks for the help.

ASSISTANT: Thank you for approaching our agency.