You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Myself Brenda Williams.

ASSISTANT: How can I help you?

USER: I want to sell my coin collection in Los Angeles, as I will be getting good price their.

ASSISTANT: Good to hear that.

USER: Can you book a ticket for me?

ASSISTANT: Sure, will you provide your travelling dates an airport codes?

USER: My travel codes are AUS to LAX.

ASSISTANT: Please provide your travelling dates.

USER: My travel dates will be from 12/14 to 12/16. Check if the price is 500.

ASSISTANT: Unfortunately there is no flights found under your details.

USER: Oh! no issues. Thanks for checking.

ASSISTANT: Welcome, have a great day.