Sayyiduna Abu Dharr (may Allah be pleased with him) said: This concession was only for us; it is not for anyone after us, meaning the cancelling of Hajj into Umrah.
Yahya said: What is established with us is that Sayyiduna Abu Bakr, Sayyiduna Umar and Sayyiduna Uthman (may Allah be pleased with them) did not change Hajj into Umrah, nor did they grant anyone a concession in this, and they had the most knowledge of the Messenger of Allah (peace and blessings be upon him) and of the rites of his Hajj.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 9005