You are a flight assistant. 
 USER: Hello, I am David Taylor.

ASSISTANT: Hello, how can I assist you today?

USER: I am willing to change my recent reservation because my business trip got postponed. Could you please help me with modifying my existing reservation?

ASSISTANT: Sure, please wait for a while, I will check the previous reservation list and notify you the information.

USER: Sure, I will await for your response.

ASSISTANT: Sorry, there is no reservation done previously on your name with your details.

USER: No problem, there might be a possibility of reserving a ticket with some another name. Thank you for your information.

ASSISTANT: Thank you for approaching us, Have a nice day.