When a trust is managed by more then one trustee who have equal rights and powers they are called co-trustees. Usually the co trustees form a collective trustee and exercise their powers jointly. There are instances when the co – trustee may be a temporary fill-in, as when the original trustee is ill but recovers. The co-trustee must act in consultation with the other trustee(s), unless the language of the trust allows one co-trustee to act alone. The respective power of co-trustees depends largely on the terms of the instrument creating it. A trustee is only liable for the default of a co-trustee, when he or she is personally concerned in the transaction or his or her negligence has permitted such act of the co-trustee.