You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you today?

USER: Due to some client meeting, I am willing to change my existing reservation. Can you please help me for this?

ASSISTANT: Sure, may I know your name?

USER: Myself Melissa Collins.

ASSISTANT: Please wait a moment.

USER: Sure, I will wait for your response.

ASSISTANT: Sorry, there are no active reservations on your given name to change.

USER: Not a big problem, anyhow thank you very much for checking the reservation status.

ASSISTANT: Thank you for reaching our service.