You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I be of your service?

USER: I need to change my existing reservation as my exams got postponed, Can you please help me with that?

ASSISTANT: Sure, I'll try to help you in changing an existing reservation. Can I have your name to check the reservation status?

USER: Robert Taylor here.

ASSISTANT: Ok, please wait a minute I will get back to you with the present status.

USER: Sure.

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

USER: Ok, no problem.

ASSISTANT: Thank you for approaching us.

USER: Thanks for your information.