Upon commencement of a civil action, the complaint must not seek punitive damages. After filing the suit a party may make a motion to amend the pleadings to claim punitive damages. The motion must allege the applicable legal basis under section 549.20 or other law for awarding punitive damages in the action and must be accompanied by one or more affidavits showing the factual basis for the claim. At the hearing on the motion, if the court finds prima facie evidence in support of the motion, the court shall grant the moving party permission to amend the pleadings to claim punitive damages. For purposes of tolling the statute of limitations, pleadings amended under this section relate back to the time the action was commenced.