Verb (used without object) : The aging founder of the firm decided to abdicate.    From Dictionary.com. 

Verb (used with object) : King Edward VIII of England abdicated the throne in 1936.    From Dictionary.com. 

At that time, Elizabeth Bowes-Lyon was the duchess of York, sister-in-law of Edward the abdicator.    From Wordnik.com.  [CNN Transcript Mar 30, 2002] Reference

My dictionary defines quitter as "one that quits", it is also a synonym for abdicator: "one who formally relinquishes an office or responsibility".    From Wordnik.com.  [Palin says she is not a quitter] Reference

In the twelfth century, it happened that a Mikado, particularly alive to the vanities of the world, not only gave up his station to his son, then three years old, but also renounced the labors of the regency, which were intrusted to the infant monarch's grandfather, whose first exercise of power was the immediate imprisonment of the abdicator.    From Wordnik.com.  [The Atlantic Monthly, Volume 05, No. 32, June, 1860] Reference

The powerful Creoles of Santa Fe de Bogota didn’t actually declare independence from Spain, the declared allegiance to the abdicator, Fernando VII of Spain.    From Wordnik.com.  [20 Julio de 1810 « Unknowing] Reference