Diebold Inc. said it will restate its results for the four years ended 2006 and the first quarter of 2007 to revise its method of recognizing revenue. The changes are in response to discussions with Securities and Exchange Commission.

In addition, the company, which makes automated teller machines, security systems, and voting machines, said management’s report on internal controls over financial reporting contained in its 2006 annual report should no longer be relied upon.

The accounting issue involves the company’s prior practice of recognizing certain revenue on a “bill-and-hold” basis.

Revenue previously recognized under the company’s prior bill-and-hold practice now will be deferred until a customer accepts a product at a customer location. This change should not, however, alter the timing of billing and collections, so operating cash flow will be unaffected.

With a bill-and-hold system, the seller bills customers before shipping the products they bought. At the center of the controversy is the question: Exactly when does ownership of a product contractually passes to a customer.

Diebold announced in early October that it was discussing with the SEC the most appropriate revenue-recognition method to replace its bill-and-hold practice. In December the Justice Department launched its own investigation into the company’s accounting practices.