You are a flight assistant. 
 USER: Hello, I am Kimberly Lopez.

ASSISTANT: Hello. How can I aid you?

USER: I want to enjoy in Beer festival with my friends at Dallas & Fort Worth, TX - DFW. Can you please book a ticket under price 500?

ASSISTANT: Ok, I am here to help you. Mean while may I know your travelling dates?

USER: Sure, I will depart on 07/26 and return on 07/28.

ASSISTANT: Can you please mention your source airport code?

USER: Sure, my nearest boarding airport is Oakland, CA - OAK.

ASSISTANT: Ok, please wait for a while I will check and let you know about the availability of flight ticket.

USER: Sure.

ASSISTANT: Ok, thank you for waiting. Sorry, I did not find any flight ticket on your preferable dates.

USER: Ok, no issues. Thank you for your help.

ASSISTANT: Thank you for reaching us.