Pope Benedict XVI is making changes to speed up the process of choosing his successor.
Under an order he signed today, the conclave can start before the usual 15 day transition period if all the members of the College of Cardinals are at the Vatican.
With Holy Week beginning March 24, a new Pope would need to be installed by March 17.
One person who will not take part in the conclave is Britain's highest-ranking Catholic leader.
Pope Benedict has already accepted the resignation of Cardinal Keith O'Brien, the Archbishop of St. Andrews in Edinburgh.
The Observer newspaper reports he is resigning amid allegations abuse, leveled by three priests and one former priest.
O'Brien denies the allegations, which the paper says date back to the 1980's.
Benedict will become the first Pope to resign in 600 years when he steps down Thursday.
The 85-year-old said he's not abandoning the church, but rather passing the torch to someone in better health.
Cardinal Timothy Dolan will be among those traveling to the Vatican to choose a new Pope.
He plans to leave tomorrow for Vatican City.