You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I be at your service?

USER: My brother said me to change his reservation because he want to stay for some more days at grandfather's place in Washington. Can you please help me out to change his reservation?

ASSISTANT: Sure, May I know your name to check the reservation list?

USER: Sure, his name is Mary Taylor.

ASSISTANT: Ok, please wait.

USER: Ok.

ASSISTANT: There is no reservation found by this name.

USER: Not an issue, thank you for checking.

ASSISTANT: Thank you for choosing us.