You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, How may I be of your help?

USER: I want to change My existing reservation,will you help me?

ASSISTANT: Sure, May I know your good name please?

USER: My name is Barbara Walker.

ASSISTANT: Ok, please wait for a minute. I will revert to you. Thank you for waiting.

USER: No problem.

ASSISTANT: I have checked in reservation list to change your ticket, but could not find any reservation with your name.

USER: OK,not an issue.

ASSISTANT: Thanks for connecting with us.

USER: Thank you.