You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Jeffrey Brown.

ASSISTANT: How can I assist you today?

USER: Can you please change my existing reservation? because my sister reserved me a ticket with a wrong airport and location.

ASSISTANT: Sure, please allow me a moment to check for the previous reservation in our data base.

USER: Ok.

ASSISTANT: Jeffrey, there is no reservation found under your name.

USER: No problem, thank you for checking.

ASSISTANT: Thank you for contacting us.