When you upend something, you flip it over or tip it on one side. Tell your sister you won’t play checkers with her anymore if she continues to upend the board angrily every time she loses.
To move the table from one room to another, you might have to upend it so it’ll fit through the door, resting it on one end. The other way to upend something is to invert it, or turn it onto the opposite side, the way you upend a bottle of root beer over a glass or upend your school bag and shake the contents onto your bed to find that lost pack of gum.
become turned or set on end
set, turn, or stand on end