You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I guide you?

USER: I want to change an existing reservation, so please help me in changing the reservation.

ASSISTANT: Sure, I am happy to guide you to change the ticket details once I have found your previous reservation. Can I know your name please?

USER: Myself Jeffrey Wright.

ASSISTANT: Ok, I need sometime to check your ticket status in our portal. Can you please wait a minute?

USER: Ok.

ASSISTANT: When I have checked your ticket status, I didn't found any reservation under your name to modify the details.

USER: Not an issue. Thank you.

ASSISTANT: You are most welcome. Thank you for choosing us.