(b) A matter of form or substance in an indictment or information may also be amended after the trial on the merits commences if the defendant does not object.

(c) An indictment or information may not be amended over the defendant's objection as to form or substance if the amended indictment or information charges the defendant with an additional or different offense or if the substantial rights of the defendant are prejudiced.

Acts 1965, 59th Leg., p. 317, ch. 722, Sec. 1, eff. Jan. 1, 1966. Amended by Acts 1985, 69th Leg., ch. 577, Sec. 1, eff. Dec. 1, 1985.