You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I be of your assistance?

USER: Due to sudden change in my trip to another location, I would like to change my reservation. Can you please help me updating my reservation which was made on the name of Gregory Mitchell?

ASSISTANT: Sure, we are here to help you. Can you please wait for a moment, I will check with your reservation.

USER: Sure.

ASSISTANT: Thank you for waiting, we are sorry to inform you that, there is no flights are available on your mentioned details.

USER: That's fine. thank you.

ASSISTANT: Thank you for your response.