Is it permissible to change from Tamattu' to Ifrad?

It is not permissible or possible to change from Tamattu' to Ifraad. Rather, it is permissible to change from Ifraad to Tamattu' by converting one's ihram for Hajj into 'Umrah, thus becoming a Mutamatti'. It is also permissible for the Qaarin to change his intention from Qiraan to 'Umrah, thus becoming a Mutamatti', except if he has already brought the sacrificial animal (hady) in both cases, in which instance it is not permissible for him to do so.