You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I assist you for the day?

USER: Donald Thompson here.

ASSISTANT: Ok.

USER: I have planned to meet my colleagues who are staying in Boston, but due to heavy rainfall at my place it has been postponed.So I would like to alter my existing reservation. Would you please assist me in changing?

ASSISTANT: Sure, I am here to help you. Sorry, we found no reservation on your given name.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for reaching us.