defense of the suit against him. However, Rule 15.03 requires more than simply showing that the potential new defendant had been made sufficiently aware of the commencement of the action. “The second requirement is that each potential new party must have known that but for a misnomer or mistake concerning his or her identity, the action would have been brought against him or her.” Rainey Bros. Constr. Co. v. Memphis & Shelby County Bd. of Adjustment, 821 S.W.2d 938, 941 (Tenn.Ct.App.1991) (citing Lease v. Tipton, 722 S.W.2d 379, 380 (Tenn.1986)). “A ‘mistake’ within the meaning of this rule does not exist merely because a party who may be hable for conduct alleged in the original complaint was omitted as a party defendant.” Smith, 776 S.W.2d at 109; see also Lease, 722 S.W.2d at 380 (<HOLDING>). It is the plaintiff that has the burden of
holding that cornwell was not required to sue them and her failure to do so in the original complaint in light of her obvious knowledge and the detailed nature of that pleadings exhibit must be considered a matter of choice not mistake holding that a district court had sufficient reason to reject the plaintiffs belated attempt to amend her complaint fifteen months after the commencement of her action and nine months after the initial amendment to her complaint holding that plaintiffs motion to amend her complaint to add her husband as a defendant did not relate back because her failure to sue her husband was not due to misnomer or mistake involving the identity of the proper party but because the law at the time of the complaint did not allow one spouse to sue another in tort holding a wife liable for necessary medical expenses incurred by her husband under the doctrine even though the wife did not sign as a guarantor and did not request that her husband be admitted nor anticipate that her husband would be admitted holding that the plaintiffs second complaint did not relate back to her first complaint because her second complaint was not an amendment to her first complaint but rather a separate filing