Variables can only be reset using the mapping functions ClearVariable, ClearVariables or ClearAllVariables(see below) , since a rule with an empty string is not executed!

ClearAllVariables (['ExlcudeVariablenName1, ExlcudeVariablenName2'])

Resets all variables:

ClearAllVariables()

Resets all variables except variables named HeaderGln and HeaderSupplier:

ClearAllVariables ('HeaderGln, HeaderSupplier')