Like Lookman?It's called recognizing that you made a mistake and cutting your losses.
NB Lookman is a bit of an extreme example as it’s taken him several years to reach any sort of potential - which he and Everton didn’t have the patience for.
My opinion remains though, he’s not shown himself to be as entirely unsuited to this league as say Koldrup or Klassen so I’m not ready to draw a line under his sign just yet.