Invalidate-argument

invalidate-argument
    Invalidate-argument (Conditional operator)
    Removes an argument from future consideration as a special data item.
    Takes 1 or more arguments...
    All: The argument to remove from the preceding argument list.

Comments

Using this is required if you intend to cycle through a list of non-recurring arguments in an event based on every-time-argument. Otherwise, an argument remains valid even after it has been used once.