Indiana Code Title 34. Civil Law and Procedure § 34-36-3-2

Sec. 2. (a) In a civil case, the court may direct that no more than three (3) jurors be called and impanelled, in addition to the regular jury, to sit as alternate jurors.

(b) Alternate jurors shall, in the order in which they are called, replace jurors who, before the time the jury returns its verdict, become unable or disqualified to perform their duties.

(c) Alternate jurors:

as regular jurors.  An alternate juror who does not replace a regular juror shall be discharged after the jury brings in its verdict.