You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I assist you?

USER: I want to change my existing reservation which is done recently due to some problems, can you please help me in this?

ASSISTANT: Sure, may I know your name please?

USER: Sure, my name is Elizabeth Campbell.

ASSISTANT: Please give me a moment.

USER: Sure, I will wait.

ASSISTANT: There is no reservation found with your given name.

USER: Ok, not an issue. Thank you for your service.

ASSISTANT: Thank you for opting us.