You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: I want to change my existing reservation due to some issues, can you please help me with that?

ASSISTANT: Sure, I am here to help you. May I know your name please to check your reservation status?

USER: Sure, I am Dorothy Garcia.

ASSISTANT: Dorothy Garcia, no reservation has been found on your name in our database.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: Thank you for choosing us.