You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, what help are you seeking for?

USER: I am Timothy Collins.

ASSISTANT: Yes Collins, I am here to guide you.

USER: I want to postpone my trip to Houston because of financial problems, so I want to change my existing reservation.

ASSISTANT: Ok, please give me a while I'll get back to you with your required details.

USER: Ok.

ASSISTANT: You have no reservation on provided name to change your reservation.

USER: That's ok, thank you for your information.

ASSISTANT: Thank you for choosing our services.