Discuss in brief the provisions for filing an appeal before the Natinoal Company Law Appellate Tribunal (NCLAT) under the Companies Act, 2013.

Section 421 of the Companies Act, 2013 deals with appeal from orders of National Company Law Tribunal and provides as under: Any person aggrieved by an order of the National Company Law Tribunal may prefer an appeal to the National Company Law Appellate Tribunal. No appeal shall lie to the National Company Law Appellate Tribunal from an order made by the National Company Law Tribunal with the consent of parties. Every appeal shall be filed within a period of forty-five days from the date on which a copy of the order of the National Company Law Tribunal is made available to the person aggrieved and shall be in such form, and accompanied by such fees, as may be prescribed: Provided that the National Company Law Appellate Tribunal may entertain an appeal after the expiry of the said period of forty-five days from the date aforesaid, but within a further period not exceeding forty-five days, if it is satisfied that the appellant was prevented by sufficient cause from filing the appeal within that period. On the receipt of an appeal, the National Company Law Appellate Tribunal shall, after giving the parties to the appeal a reasonable opportunity of being heard, pass such orders thereon as it thinks fit, confirming, modifying or setting aside the order appealed against. The National Company Law Appellate Tribunal shall send a copy of every order made by it to the National Company Law Tribunal and the parties to appeal.