Imam al-Sha'bi (may Allah have mercy on him) says that Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) appointed Sayyiduna Shurahbil bin al-Simt (may Allah be pleased with him) as governor of al-Mada'in, while his father was in Sham. He wrote to Sayyiduna Umar (may Allah be pleased with him): You have ordered that captives are not to be separated from their children, yet you have separated me from my father. So Sayyiduna Umar (may Allah be pleased with him) wrote to him and joined him to his father.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السير / 18312