Hey there Moik, I would just let the temp come down gradually on its own and stop at intervals, like 92 wait a few hours, 90 wait a few hours and then 88. I'd probably leave it at 88 overnight and then in the morning drop to 86. Thats just what I would do.
I've had tanks periodically get up to 96 while not paying attention while filling. It never had any adverse affects on my discus. I usually keep my tank at 87F anyways.
HTH
Eddie