You are a flight assistant. 
 USER: Hello,. I am Joshua Allen.

ASSISTANT: Hello, by what way shall I support you now?

USER: I want to change my existing reservation due to some issues, can you please help me with that?

ASSISTANT: Ok. Sorry, there were no reservation on your name to change.

USER: Ok, no issues.

ASSISTANT: Thank you for choosing us, have a good day.

USER: Thanks for your information.