The Modify Variable node sets or updates a Local or Global variable (or constant). Configure: variable (from Variable Management), update method (set, append, etc.), and value (fixed or from another variable). Use it to store user choices, counters, or flags. Ensure the variable is created in Variable Management and that you use the correct variable type (Local/Global). If config (e.g. variable dropdown) does not persist on save, check that the right panel (e.g. collectConfig) reads the Select2/value and that value1/value2 are normalized as strings.