You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I would like to change my existing reservation, can you help me in that?

ASSISTANT: Sure, I am here to help you with that, can I know your good name to proceed further?

USER: Sure, myself Sandra Thompson.

ASSISTANT: Thank you. Please be online for a while. I will check your reservation status and get back to you.

USER: Sure, I will wait for your response.

ASSISTANT: I am sorry to say you that there is no reservation found under your name in our database.

USER: That's ok, no problem. Thank you for the information.

ASSISTANT: Thank you for reaching us.