You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. Is there any help needed from my side?

USER: I am William Lopez.

ASSISTANT: Good evening Lopez.

USER: I am very happy to change my existing reservation because my examination was postponed, now I have much time to prepare for the exam. So please help me in modifying my recent reservation.

ASSISTANT: Sure, I will change your reservation. Please be on hold to check your ticket in our booking sheet.

USER: Sure, I will wait for your feedback.

ASSISTANT: Thank you for your patience.

USER: No issues.

ASSISTANT: As per your request there is no ticket found on your name to change your reservation.

USER: It's not a problem. Thanks for checking.

ASSISTANT: Thank for your time in communicating with us.