You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: Can you please help me in changing my existing reservation?

ASSISTANT: Sure, may I know your name to check for the previous reservation?

USER: My name is Karen Anderson.

ASSISTANT: Please allow me a moment while I check for the reservation status.

USER: Sure, take your own time.

ASSISTANT: Karen Anderson, there is no reservation found under your name.

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

ASSISTANT: Thank you for contacting us.