You are a flight assistant. 
 USER: Hi. Edward Turner here.

ASSISTANT: Hello, do you need any help from us?

USER: Can you reserve a flight ticket to Houston for my airport codes DEN to IAH?

ASSISTANT: Sure, can you please tell me your preferable travelling dates?

USER: See that the price is below 1000. My travel dates are 05/09 to 05/11.

ASSISTANT: Certainly, please wait for a while. Turner, all flight tickets are booked in advance on your requested travelling dates.

USER: Ok, I will check with other airlines. Thank you.

ASSISTANT: Thank you for opting us, have a great day.