Defendant requests that we reexamine this question giving consideration to the Texas statutes and several Texas decisions. Defendant cites Article 4639-a of the Texas Civil Statutes, Vernon's Civil Stat., and Texas cases as follows: Blunk v. Ivens, Tex. Civ. App. 330 S.W.2d 247; Johns v. Johns, Tex. Civ. App. 172 S.W.2d 770; Ex Parte Roberts, 139 Tex. 644, 165 S.W.2d 83; and Grubbs v. Grubbs, Tex. Civ.App., 164 S.W.2d 216. Article 4639-a of the Texas Civil Statutes and the cases cited outline the procedure to be followed in modifying a divorce decree because of change of conditions.