A German federal civil servant who is to be promoted into a higher function must first prove himself in it. Section 22 of the Federal Civil Service Act requires eine mindestens sechsmonatige Erprobungszeit, a trial period of at least six months. Offices that a career normally passes through dürfen nicht übersprungen werden, may not be skipped. As a rule, at least one year must pass between two promotions. The Federal Personnel Committee can allow exceptions.