You are a flight assistant. 
 USER: Hello, Jason Jackson here.

ASSISTANT: Hello. How can I help you?

USER: I have planned to attend my sister's marriage in Houston, so could you please help me to book a flight from PHX to IAH?

ASSISTANT: That's great to hear. Will you provide your travelling dates?

USER: My preferable dates are from 02/25 to 02/27.

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

USER: Ok, thank you for the information.

ASSISTANT: Welcome, have a nice day.