Yes, in order to transfer the assets held in another voluntary pension fund to a voluntary pension fund managed by BT Pensions, it is necessary to become a participant in the fund managed by BT Pensions by signing a membership deed to this effect in any Banca Transilvania unit. 

You can then apply to transfer from your current voluntary pension fund to the Pillar 3 fund administered by BT Pensions. This application is submitted to the administrator of the fund you are leaving.