You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Myself Sarah Robinson from Las Vegas.

ASSISTANT: How can I assist you today?

USER: I want to change my travel dates in my previous reservation. Can you please help me with that?

ASSISTANT: Sure, i can help you with that. Please wait a moment.

USER: Ok, thank you.

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

USER: Oh! It's ok no problem. Thank you for your service.

ASSISTANT: Thank you for opting us.