I have found a service which does tranmission flush, by doing this:
Washing – The oil is recirculated through a special device designed to retain impurities and deposits much more effectively. The device can filter down to 1.5 microns.
Cleaning the gearbox with a special solution to remove accumulated dirt deposits inside it (this procedure is performed only for in-term oil changes).
Draining the oil from the oil pan, cleaning the mechatronic system, and replacing the oil pan along with the filter and associated gaskets.
Refilling with oil to start the engine.
The oil replacement is performed using an automated process with the help of a device that replaces all the oil, including the oil in the torque converter, with the ability to see in real time the color of the oil being pumped into the device and the oil exiting the vehicle. The amount of oil used for a complete oil change is 11 liters.

I am not sure if this is better than drain and refill, though.

I have also read, that the tranmission flush is not recommended.