You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you from flight booking agency?

USER: Due to sudden weather change, I would like to change my existing reservation. Can you help me?

ASSISTANT: Sure, I am here to help you. May I know on whose name you have done the reservation previously?

USER: Please check with the name Thomas Phillips.

ASSISTANT: Ok, give me a moment please.

USER: Sure.

ASSISTANT: I have searched the database with your name Thomas Phillips, I couldn't find any reservation with your name to change it.

USER: That's fine, thank you for the information.

ASSISTANT: Thank you for contacting us.