You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: My name is Justin Perez, can you please help me in changing my existing reservation details?

ASSISTANT: Sure, please wait for some time.

USER: Ok.

ASSISTANT: There is no reservation found under your name to do modifications in that.

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

ASSISTANT: Thank you for choosing us.