La. Code Civ. Proc. art. 2133

A. An appellee shall not be obliged to answer the appeal unless he desires to have the judgment modified, revised, or reversed in part or unless he demands damages against the appellant. In such cases, he must file an answer to the appeal, stating the relief demanded, not later than fifteen days after the return day or the lodging of the record whichever is later. The answer filed by the appellee shall be equivalent to an appeal on his part from any portion of the judgment rendered against him in favor of the appellant and of which he complains in his answer. Additionally, however, an appellee may by answer to the appeal, demand modification, revision, or reversal of the judgment insofar as it did not allow or consider relief prayed for by an incidental action filed in the trial court. If an appellee files such an answer, all other parties to the incidental demand may file similar answers within fifteen days of the appellee's action.

B. A party who does not seek modification, revision, or reversal of a judgment in an appellate court, including the supreme court, may assert, in support of the judgment, any argument supported by the record, although he has not appealed, answered the appeal, or applied for supervisory writs.