When inventors talk about amending a patent, they usually mean amending a patent application. Amendments of patent applications are done in response to an Office Action from the U.S. Patent and Trademark Office. Office Actions are official communications from the USPTO that contain the patent examiner's criticisms of the application. Responding to an Office Action often involves amending the patent application. This is often a necessary step before a patent is allowed.
Read the Office Action from the U.S. Patent and Trademark Office. Pay particular attention to the "Period for Reply," which provides information on the deadline for your response. Find the sections titled, "Disposition of Claims" and "Application Papers." Carefully note which claims are objected to or rejected. Make sure you understand the examiner's basis for making the objection or rejection. Review how the patent examiner wants the application papers changed.
Determine whether you need to amend the claims. Often the examiner provides prior art that is similar to your invention. In this case, you want to amend your claims so that they are not described in the prior art. Alternatively, the examiner might not understand the invention. If this is the case, the best approach is to politely explain why the claim should be allowed.
Using a computer, copy all of the claims into a new document. If you wish to amend claims by adding text, enter the new text and underline it. If you wish to amend claims by deleting text, strike through the existing text or place in double brackets to signify you wish to delete it.
Determine whether you need to amend the filing papers. The patent examiner may request that you amend the patent application to eliminate typographical errors.This is done by following the process set forth in step three. Added text should be underlined; deleted text should be struck through or placed in double brackets.
Submit your response to the Office Action to the USPTO following the instructions you received. Use the same customer number -- and digital certificate if applicable -- you used when filing the application originally.