When a Governor seat becomes available because he appointed for other federal position or is running for president, a special election must be held to elect a new governor to finish the term that the last one left empty.
Special election refers to a form of election that conducted before the working period of those who held the previous position officially ended. This tend to happen when the previous holder of the position is unable to resume the duty due to death/illness. Or if the previous position holder is forcefully removed for misbehavior.
