You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Margaret Smith.

ASSISTANT: Margaret, how may I help you?

USER: I would like to shift my planned dates to some other dates. Could you please help me in changing my existing reservation?

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

USER: Ok, take your time.

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

USER: Its ok, thank you for the information.

ASSISTANT: Thank you for reaching us.