Yahya related to me from Malik, from Ibn Shihab, from Said ibnal-Musayyab, that Umar ibn Abi Salama once asked Umar ibn alKhattabfor permission to do umra in Shawwal. He gave him permission, so hedid umra and then went back to his family, and he did not do hajj.
USC-MSA web (English) reference: Book 20, Hadith 59
Arabic reference: Book 20, Hadith 764