You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I assist you?

USER: I am Alexander Lewis, help me to change my reservation.

ASSISTANT: Sure, please wait for a while. I will check your reservation status.

USER: Please check my details in your records.

ASSISTANT: There is no reservation found under your name, Lewis.

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

ASSISTANT: Thank you for choosing our service.