The post contains answer to questions “What is Hajj al Tamattu? Who can perform Hajj al Tamatu? How to perform it? What are the rituals of it? What are its steps?”
What is Hajj al Tamattu?
In Hajj al Tamattu, Ummrah should be performed before undertaking Hajj.
When a Muslim perform Umrah without an initial intention of performing Hajj and exile from the state of Ihram but after the start of pilgrimage in Mecca, he/she suddenly made up of his/her mind of performing Hajj, then such Hajj would be called as Hajj al Tamattu.
In other words we can say that Hajj al Tamattu is performed when a pilgrim performs Ummrah before the start of pilgrimage in Mecca. After Ummrah he/she exiles from Ihram state but when Pilgrimage starts he/she performed Hajj, then such Hajj is called Hajj al Tamattu.
A person who performs Hajj al Tamattu is called Mutamatti. Hajj al Tamattu is the most easiest and convenient form of Hajj.
Source: Above answer is based on information given in Hajj books.