A irrevocable trust is a permanent trust. Once it is created and in operation, it cannot be revoked, amended, or changed in any way. However, in some cases, it may be possible to change after consent of the beneficiary. However, irrevocable trusts offer tax advantages that revocable trusts don't. For exmple, it allows a person to give property and assets away even before death. Effectively, since the asset and property is no longer the trustmakers, the tax liability and responsibility is also no longer he trustmakers.