In legal jargon, it’s the trustee, who is charged with managing the trust assets, who is generally also responsible for providing information about the transactions. Beneficiaries are those named to
get the trust assets.
How and whether you can change the trustee depends on what the document says. Some irrevocable trusts permit a change of trustee, and usually specify that a new trustee may be appointed by a third party, often called the special trustee.
Look at the document itself, which will usually specify how and in what circumstances a trustee may be removed. Also, if a trustee is grossly negligent, stealing from a trust, or blatantly violating a specified duty to give regular accountings to the beneficiaries, state laws will generally permit you to petition a court to remove and replace him or her.
But if you're simply not happy with how the trustee is doing, that's usually not enough for a court to step in and remove him or her from the position. Some states permit a change in trustee with the consent of all the trust's beneficiaries, but that depends on particular state, so you'd need to find out what your options are where you live.
You may get some basic guidance on this through an Internet search of “irrevocable trust and trustee and remove,” along with the name of your state. Or contact an experienced estate planning lawyer for help. Friends or family members may be able to provide the names of reputable local lawyers—or you can contact the local state bar association for names of a few to check out on your own.