Aircon bus: Khon Kaen - Udon Thani - Khon Kaen

Can somebody help me with a airco buscompany and schedules from Khon Kaen to Udon Thani and back to Khon Kaen.
I can only find the airco busroute Bangkok to Udon Thani, and I don’t need this busroute,
because this bus is by one-stop in Khon Kaen the most time full.

The VIP 1st class Blue bus is hit or miss getting a seat, no reservation for this short leg. Go to the 2nd class Orange bus station (sorry I can't remember the street but it's the BIG street near all govt. offices. Walk all the way to the back of the station or just say "Udon". Someone will walk you to the bus. You can get an A/C orange bus every 20 minutes to Udon. I used to go back & forth every week, trip takes about 1 1/2 hours. Some of the buses are very nice so if you don't like the 1st one leaving, just wait 20 minutes for the next.

I forgot to mention the bus runs between Khonkaen - Udon - back only so you can always get a seat.

Go to the bus station just down the street from Robinsons and ask for a bus to Khon Kaen. There are air con buses (and non aircon buses) coming and going to Khon Kaen all day long and into the night as well. The bus station is just behind the 7/11.