You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: Due to some issues that occur in my trip I want to change the dates of journey, can you please help me in changing my ticket?

ASSISTANT: Ok, may I know your name please to proceed further?

USER: My name is Robert Campbell.

ASSISTANT: There is no reservation found with your details, Robert.

USER: Ok, that's fine, thank you for your information.

ASSISTANT: Thank you for choosing us.