The Dalai Lama hopes to relinquish political power as the head of Tibet's government-in-exile. He has asked the Tibetan parliament to amend the constitution and seeks the speedy election of a new prime minister to lead the country.
The reason for the alteration is likely the Dalai Lama's anticipation of death. When he dies, China will pounce on the opportunity to replace him (as they have attempted to usurp the Catholic church by installing their own bishops) and will pressure foreign countries which recognize the Dalai Lama to abandon Tibet in his absence. As proof, President Obama today announced that he will not meet with the Dalai Lama during his visit to Washington this week, and has postponed a scheduled meeting until after a summit with China next month. Tenzin Gyatso, the Dalai Lama, is attempting to preserve the political existence of Tibet.
The last theocracy of Asia will thus soon vanish, leaving only the Holy See at Vatican City under the authority of the Pope in Europe and, arguably, several Middle Eastern and African Muslim nations as the world's remaining theocracies.