You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

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

ASSISTANT: Please share your name to proceed further?

USER: Myself Frank Anderson.

ASSISTANT: No reservation found in our database.

USER: Not an issue. Thank you.

ASSISTANT: Thank you for the help. Have a good day.