Whenever a head of state is not available for any reason, constitutional provisions may allow the role to fall temporarily to an assigned person or collective body. In a republic, this is - depending on provisions outlined by the constitution or improvised - a vice-president, the chief of government, the legislature or its presiding officer. In a monarchy, this is usually a regent or collegial regency (council). For example, in the United States the vice-president acts when the president is incapacitated, and in the United Kingdom the queen's powers may be delegated to counselors of state when she is abroad or unavailable. Neither of the two co-princes of Andorra is resident in Andorra; each is represented in Andorra by a delegate, though these persons hold no formal title.