Obtain the consent of the trustee and all of the beneficiaries to your termination of the trust. State laws allow for the termination of irrevocable trusts in certain circumstances, as long as the rights of the beneficiaries are protected.
Draw up a simple form entitled "Revocation of Trust." Templates for this form are available online and can be downloaded and filled out, or filled out online and then printed. The document should have in its heading, the legal name of the trust, as well as the name and address of the trustee. The body text should have simple language to the effect that the trust is terminated, and as of what date; the document should also direct the trustee to surrender control of all assets in the trust to yourself or your designated agent.
Date the revocation and sign in the presence of a witness or notary public. The witness or notary may not be the trustee. The effective date of the revocation should be the date you sign, if at all possible. The revocation should be appended to the original trust documents and kept in a safe place.
Provide a copy of the revocation and the original trust documents to the trustee by certified mail, which documents the date they are delivered by the post office. Alternatively, serve the revocation by a private delivery service or process server. To avoid misunderstandings and litigation, it is vital to inform the trustee of your intentions beforehand -- and have proof of the date that the trustee had the revocation in his possession.