You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you today?

USER: Betty Smith here. Can you please help me in changing my existing reservation?

ASSISTANT: Sure, I'll help you in changing an existing reservation.

USER: Thank you.

ASSISTANT: Ok, please wait a moment.

USER: Sure.

ASSISTANT: Thank you for waiting.

USER: My plaeasure.

ASSISTANT: Sorry, there is no reservation found by this name.

USER: Not an issue, thank you.

ASSISTANT: Thank you for availing us.