You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you today?

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

ASSISTANT: Sure, may I know your name please?

USER: Ok, my name is Michael Gonzalez.

ASSISTANT: Ok, please wait for a moment.

USER: Sure, I will wait.

ASSISTANT: Sorry, there was no reservation found with your given name.

USER: Ok, no problem. Thank you for your service.

ASSISTANT: Thank you for opting us.