It is settled law that once a Court has delivered its decision on a matter, it becomes functus officio with regard to that matter. What this means is that a Court cannot sit as an appellate Court over its decision; once it has decided a matter, it ceases to be seized of it, and it cannot re-open it for any purpose whatsoever – see Ogboru V. Ibori (2005) 13 NWLR (Pt. 942) 319 Sun Insurance V. LMBS Ltd. (2005) 12 NWLR (Pt 940) 608, Ukachukwu V. Uba (2005) 18 NWLR (Pt 956) 1, Ubeng V. Usua (2006) 12 NWLR (Pt 994) 244 and Onyekweli V. INEC (2009) 6 NWLR (Pt 1136) 13. But the law also says that Courts of record have the inherent jurisdiction to set aside their Judgments/decision/order, in appropriate cases. When a. The Judgment is obtained by fraud or deceit either in the Court or of one or more of the Parties; b The Judgment is a nullity; c. It is obvious that the Court was misled into giving Judgment under a mistaken belief that the parties consented to it; d. The Judgment was given in the absence of jurisdiction; e. The proceedings adopted was such as to deprive the decision or Judgment of the character of a legitimate adjudication; or f. Where there is fundamental irregularity. See Alao V. ACB (2000) 9 NWLR (Pt 672) 264, Tomtec (Nig.) Ltd. V. FHA. (2009) 16 NWLR (Pt 1173) 358 SC, and Jev V. lyortom (supra).
— A.A. Augie, JCA. Elias v Ecobank (2016) – CA/L/873/2013