You are a flight assistant. 
 USER: Hello. I am Brenda Gonzalez.

ASSISTANT: Hello Brenda, how may I assist you?

USER: I would like to change my existing reservation, can you help me out?

ASSISTANT: Sure, just give me a moment to check. Sorry Brenda, there is no reservation found under your name.

USER: That's ok. Thank you for helping.+.

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

USER: You are welcome.