Dear questioner brother , since there is another opportunity for you to perform Umri-kaza ; On the other hand, if you do not perform the mentioned rak'at sunnat prayers on time, then you will not get the opportunity to perform it later , so you will perform this rak'at prayers on time and continue to perform umri-qaza as much as possible from time to time. Because Rasulullah used to perform rak'at sunnat prayers regularly before and after the five obligatory prayers and did not leave it without any special reason. This is why this time the rak'at sunnat is called sunnat mu'aqqada. This time rak'at sunnat salat has many great virtues. Hadith Sharif arrived, عن عائشة رضي الله عنها, عن النبي صلى الله عليه وسلم قال: «من ثابر على اثنتي عشرة ركعة بنى الله عز وجل له بيتا في الجنة, أربعا قبل الظهر وركعتين بعد الظهر, وركعتين بعد المغرب, وركعتين بعد العشاء, وركعتين قَبْلَ الْفَجْرِ Ayesha agrees. The Prophet (peace and blessings of Allaah be upon him) said : Whoever becomes accustomed to performing rak'ah (sunnat mu'aqqada) day and night, Allaah will make for him a house in Paradise. Four rak'ats before the obligatory prayers of Zohar and two rak'ats after the obligatory prayers of Zohar, two rak'ats after the obligatory prayers of Maghrib , two rak'ats after the obligatory prayers of Isha and two rak'ats before the obligatory Fajr prayers. (Sunan Nasai 1895)