Indiana Code Title 3. Elections § 3-10-4-6

Sec. 6. (a) If a nominee for President or Vice President of the United States ceases to be a candidate before the nominee's ticket is officially certified, then that fact and the name and the state of residence of the nominee's successor, if any, shall be certified in the same manner as the original nominee and the successor's name shall be printed upon all ballots.

(b) If a nominee for President or Vice President of the United States ceases to be a candidate after the nominee's ticket has been officially certified, then that fact and the name and state of residence of the nominee's successor, if any, shall be certified in the same manner as the original nominee.  However, the ballots must reflect the original nominee's name, and any vote cast in the election for the original nominee shall be considered a vote for the successor.