A "successor trustee" is someone who takes over the responsibilities and duties of managing and distributing assets in a trust after the original trustee is no longer able to or chooses not to fulfill their role. Full definition
These guidelines may include the timing and method for distribution of trust assets, types of investments that can be made within the trust and naming successor trustees. (termland.com)
I asked successor trustee to sign over any rights if he has any. (biggerpockets.com)
During your lifetime you can name yourself trustee with First Bank & Trust being named as successor trustee to take control and administer your trust after your death. (firstbt.com)