Ind. Code § 8-1-7-1

Sec. 1. Any public utility operating under a license, permit, or franchise existing on May 31, 1921, from any county, city, or town within the state of Indiana shall, upon filing, at any time prior to July 1, 1923, with the auditor or clerk of any such county, city, or town which granted such license, permit, or franchise, and with the commission, a written declaration, legally executed, that it surrenders such license, permit, or franchise, receive by operation of the law, in lieu thereof, an indeterminate permit as provided in IC 8-1-2, and such public utility shall hold such permit under all the terms, conditions, and limitations of IC 8-1-2 as fully and completely as if the same had been done prior to July 1, 1915.