You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello,.

USER: I am Eric Hernandez.

ASSISTANT: How shall I help you?

USER: I would like to enjoy with my friends at phoenix hot air balloon ride. Can you help me in my reservation?

ASSISTANT: Please could you provide travel dates?

USER: I will start my journey on 11/21. I will return on 11/23.

ASSISTANT: Ok. Please specify connections limit?

USER: I need a layover in my journey.

ASSISTANT: Please mention your travel codes?

USER: My source airport code is Oakland, CA -OAK. My destination is Phoenix, AZ - PHX.

ASSISTANT: No flights are available.

USER: Ok, Thank you for reaching us, have a nice day.