You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: I would like to change my brother's reservation, as he want to enjoy for some more days with his friends in Los Angeles, can you please help me?

ASSISTANT: Ok, can you please share your brother's name for checking his reservation status?

USER: Sure, his name is Barbara Jones.

ASSISTANT: Ok, please give me a moment.

USER: Sure.

ASSISTANT: Sorry, no reservation has been found on your brother's name.

USER: No problem, thank you for checking.

ASSISTANT: Thank you for utilizing our service.