If (a) there be any defect in form in any indictments or (b) on the trial of any case there shall appear to be any variance between the allegations of the indictment and the evidence offered in proof thereof, the court before which the trial shall be had may amend the indictment (according to the proof, if the amendment be because of a variance) if such amendment does not change the nature of the offense charged. After such amendment the trial shall proceed in all respects and with the same consequences as if the indictment had originally been returned as so amended, unless such amendment shall operate as a surprise to the defendant, in which case the defendant shall be entitled, upon demand, to a continuance of the cause.
S.C. Code § 17-19-100