Try disconnecting the battery negative cable from the battery for about 30 seconds. That is sort of a universal way to restore parameters with "scheduled maintenance reminders". If that does not work, try turning the key switch to the on position and back off about ten times. Do not actually crank the engine, just to on, then off again, and repeat.
If that does not help, you may actually have to read the owner's manual. (Find it online at Husqvarna website).
And please be a "responsible" member and post back with results.

Thanks for the tips-- I'll try them!

The first place I checked was the owner's manual, and while it tells you how to change the oil, it doesn't tell you how to reset the display. Odd, isn't it?

I'll definitely post back and let you all know what worked!

Does the Husqvarna tractor use its own built-in computer, or is it a SENDEC unit? If it's a built-in computer, the techniques described above may perform the reset. But if it's a Sendec, those are self-powered by an internal battery and I am not sure if there is any way to reset them.

The Sendec's that I have seen will display the "Change Oil" symbol automatically from about 1 hour ahead of the actual scheduled time, to about 1 hour after (so it basically sits there and flashes the Change Oil symbol for two whole hours).

But these comments are based only on the Sendec. Your mileage may vary. Void where prohibited. Must be 18 years old to operate Sendec...

How many hours do you have on this LT? The reminder light IMO had nothing to do when the mower "Powering down". I dought the manufacture would create a system where the mower would not run when timed scheduled intervals reminders blink unless the oil pressure is too low (hence the oil pressure switch. there was oil on the dip stick right?)

I would start looking elsewhere. like air filter, spark plugs, throttle cable full travel, choke off, to start with. Then, I would suspect the fuel system, fuel filter, sucking air from dry rot hoses, fuel pump, and last carb. malfuction from dirt or improper float operation.

There is a reset button on the lower right side of the display, hold it in for several seconds and the hour timer will reset, while retaining the overall hours. the chng Oil Now will goo away for another 50 hours.