You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I support you today?

USER:  I am Frank Walker want to change my reservation owing an emergence at home. Can you help me in changing?

ASSISTANT: Sure, I'll help you in changing an existing reservation. Please wait a moment I will check the reservation status.

USER: Ok.

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

USER: Ok, no issues. Thank you for your response.

ASSISTANT: Thank you for opting us.