(a) Sayyiduna Abu Dharr (may Allah be pleased with him) said: The concession of tamattu' Hajj was only for the Companions of Muhammad (peace and blessings be upon him).
(b) In Sahih Muslim it is narrated from Abu Bakr bin Abi Shaybah. What he meant, and Allah knows best, was their annulling of the Hajj into Umrah: some of the Companions had said the talbiyah for Hajj and had no sacrificial animal with them, so the Messenger of Allah (peace and blessings be upon him) commanded them "to make it an Umrah", in order thereby, and Allah knows best, to put an end to their custom of regarding Umrah as forbidden in the months of Hajj.
(c) This is not permissible today.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 8884