In order to practice in a state other than the registered state the advocate needs to register himself in the respective Bar Council of the state where he wants to practice. Without registering with the State Bar Council the advocate cannot practice. He needs to complete the registration process and pay the registration fees. An advocate can be a member of multiple State Bar Councils but he has to pay the annual fees of all the State Bar Council to continue his membership in those councils.
Some states mandate leaving the last state of practice and furnishing a communication about the same from the Bar of that state. You should read the rules that come along with the registration form. There you will find the right answer. You may even directly call the Bar offfice.