You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I assist you?

USER: I am Mary Johnson. Can you help me to change my reservation?

ASSISTANT: Sure, please wait a moment I will check your details and proceed further.

USER: Sure, please check my details.

ASSISTANT: Sorry to say, there is no reservation found on your name.

USER: That is fine. Thank you for your help.

ASSISTANT: Thank you for contacting us, have a nice day.