Whoa - talk about misinformation! From this thread below, we get two different answers (in addition to the one suggested by Kobo JW from above) - and NONE of those worked! Laura's suggestion WORKED!!!!
https://www.mobileread.com/forums/showthread.php?t=82691
Sameer at kobo suggests:
"You can reset to factory from the Home screen by going into Menu > Settings > Advanced > Reset Device Now. "
George at kobo suggests this:
"Turn off the device. Turn it back on while holding the HOME button. This will trigger the factory reset. There is no YES/NO prompt - and please don't turn off the unit while it's doing this."
O...M....G...