You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you?

USER: I am Sandra Hall. I want to alter my reservation, as my exam scheduled has been postponed. Could you help me in changing?

ASSISTANT: Sure, I am happy to help you. Please wait for a while, I will check the reservation on your name to change it.

USER: Ok.

ASSISTANT: Thank you for your patience, There was no reservation found on your specified name.

USER: Ok, no issues. Thanks for your quick response.

ASSISTANT: Thank you for contacting us.