You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I assist you?

USER: Ashley Walker here.

ASSISTANT: Nice to meet you.

USER: I would like to change my existing reservation. Please help me in that.

ASSISTANT: Sure, please wait for a while.

USER: Ok.

ASSISTANT: Ashley Walker, there is no active reservation found under your name to do modifications in that.

USER: No problem, thanks for your information.

ASSISTANT: Thank you for choosing us, have a nice day.