When a sale becomes effective:
(a) Unless the purchaser provided otherwise in the application for approval of the sale or unless the commissioner provided otherwise in the approval of the application:
(1) The purchaser may establish and maintain a branch office at the head office of the seller and establish and maintain equivalent offices at the branch offices, places of business, extensions of offices, and other facilities, if any, of the seller.
(2) If the seller was authorized to transact and was transacting trust business, the purchaser, if it is a California state bank or savings association, may transact trust business.
(b) The commissioner shall issue to the purchaser certificates of authority, licenses, and other authorizations as may be necessary to carry out the provisions of subdivision (a).