Recreating a constant removes from the KB all of the assertions involving that constant, while leaving the constant itself intact. It is designed for those times when you want to get rid of old information on a constant, and start over anew.
Recreating a constant is the recommended way of starting over on a constant. Killing the constant and then creating a new one by the same name could be problematic, and thus should be avoided. Kills should be reserved for when the constant itself should be removed from the KB, not just the assertions on it.
It is impossible to reverse a recreation (short of reasserting all of the assertions that involved it before the recreation), so it is very important to be sure that killing is what is desired.
To recreate the constant and delete from the KB all assertions involving it, press the [Yes, Recreate] button. The number of assertions that will be removed are listed just above the confirmation buttons.
To leave the constant and its assertions intact and return to the previous frame, press the [No] button.