You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Myself Jack Collins.

ASSISTANT: How may I guide you?

USER: Due to some business meetings, I am going to change my existing reservation. Could you please help me in changing the reservation?

ASSISTANT: Sure, I will help you. Please wait a moment.

USER: Sure, I will wait for your response.

ASSISTANT: Jack, no reservation has been found on your name in our records.

USER: Not a big problem, anyhow thank you very much for your help.

ASSISTANT: Thank you for approaching our agency.