I bought a "Cync" bulb from GE and had to reset it, I couldn't for the life of me. This is their official video on how to do it:
You have to repeat a sequence with near perfect timing, that takes about a minute straight. Since we moved, I had to do this for 4 lights and wanted to tear my hair out, lol.
I've found that for whatever reason, "smart home" stuff is some of the worst designed and managed products out there.