Provos’s name day is October 12, the feast of Probus and Tarachos.
Churches that follow the Old (Julian) Calendar keep the same feast on October 25 of the civil calendar. See everything commemorated on October 12.
The saint behind the name

Probus and Tarachos
October 12, Martyr, Πρόβος
Saints Probus and Tarachos, together with Andronicus, were Christians of Cilicia who suffered during the persecution under Diocletian at the beginning of the fourth century. Differing in age and station, they were united in their confession; brought repeatedly before the judges, they endured prolonged tortures with astonishing endurance and were finally put to death for Christ.
Name days: Provos
What to say on a name day
The Greek wish is Χρόνια Πολλά (Chronia Polla), “many years.” A call or a short message on the day is what people remember. See name day wishes you can send and what a name day is.