You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER:  I want to change my recent reservation as my joining date got postponed. Can you help me in changing?

ASSISTANT: May I know your good name please?

USER: My name is Brian Martin.

ASSISTANT: Please give me a moment.

USER: Sure.

ASSISTANT: There is no reservation found with your given name.

USER: No problem, thank you for checking it.

ASSISTANT: Thank you for choosing us.