You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. With whom I am talking?

USER: Catherine Adams this side, please help me in changing my existing reservation because of some changes in my travelling dates. Will you please help me with that?

ASSISTANT: Sure, I am happy to help you. May I know your good name for verification of existing reservation status?

USER: Sorry, which is mentioned above that is my brother's name, please check the reservation status with the name Frank Hall.

ASSISTANT: Sure Hall, I will do that for you. Please be hold on for a moment to check the reservation status.

USER: Sure, take your time.

ASSISTANT: Thank you for waiting. Sorry Hall, I did not came across your name in the reservation chart.

USER: Oh! no issue, thank you for your help.

ASSISTANT: Most welcome. Thank you for choosing us. Have a great day.

USER: Thank you.