You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Brenda Nelson here.

ASSISTANT: What can I do for you today? Nice to meet you Brenda.

USER: My friends changed our trip suddenly to Charlotte, please change my existing reservation.

ASSISTANT: Ok, please wait a moment to search it.

USER: Ok.

ASSISTANT: Sorry Brenda,there is no reservation found on this name.

USER: Fine, thank you for your support.

ASSISTANT: Thank you for calling us.