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Notice of fiduciary relationship.
The term “fiduciary” means any person acting for another person. It applies to persons who have positions of trust on behalf of others. It generally includes a guardian, trustee, executor, administrator, receiver, or conservator. A personal representative for a decedent's estate is also a fiduciary.
Form 56.
If you are appointed to act in a fiduciary capacity for another, you must file a written notice with the IRS stating this. Form 56 is used for this purpose. See the Instructions for Form 56 for filing requirements and other information.
File Form 56 as soon as all the necessary information (including the EIN) is available. It notifies the IRS that you, as the fiduciary, are assuming the powers, rights, duties, and privileges of the decedent. The notice remains in effect until you notify the IRS (by filing another Form 56) that your fiduciary relationship with the estate has terminated.
Termination of fiduciary relationship.
Form 56 should also be filed to notify the IRS if your fiduciary relationship is terminated or when a successor fiduciary is appointed if the estate hasn't been terminated. See Form 56 and its instructions for more information.
At the time of termination of the fiduciary relationship, you may want to file Form 4810, Request for Prompt Assessment Under Internal Revenue Code Section 6501(d), and Form 5495, Request for Discharge From Personal Liability Under Internal Revenue Code Section 2204 or 6905, to wind up your duties as fiduciary. See below for a discussion of these forms.
https://www.irs.gov/publications/p559
