ERN name1 name2 name3 . . .
ERN removes the variable(s) specified by its input from the Logo workspace.
ERASE belongs to the commands which do not evaluate their input. You can supply the inputs without quoting them. If you, however, want an input to be evaluated, you can surround it with brackets.
COLOR is BLUE
NUMBER is 2
JOHN is JANE
? ERN COLOR
? ERN NUMBER (FIRST [JOHN SMITH])