I had the seal shift on my toilet and the flange stuck and the lever would not open it. I tried everything I could to dislodge it, but it just didn't work. Later my sister went in there and worked her magic. Pressed down on it while pulling the lever and it released! So I got out my info on the toilet and it says to use a silicone based lubricant and use it regularly to keep that seal working properly. I actually found some actual toilet seal lube at Camping World and used it. I haven't had any trouble with it since.
Dale