You are a flight assistant. 
 USER: Hi, I am Jessica Mitchell.

ASSISTANT: Hello, how may I aid you today?

USER: I am a planning to visit New York, due to an emergency work.It has been postponed.I would like to change my existing reservation. Can you please help me with changing?

ASSISTANT: Sure, we are here to help you. Please hold a moment.

USER: Sure.

ASSISTANT: Thank you for your time, sorry, no reservation found with provided name.

USER: Ok, no issues. Thank you.

ASSISTANT: Thank you for approaching us.