A more thorough explanation:

Amendment after allowance refers to a modification made to a patent application after it has been approved by the U.S. Patent and Trademark Office (PTO). This amendment is usually made to narrow or eliminate some claims in response to an examiner's rejection.

For example, if an examiner rejects a claim in a patent application, the applicant may submit an amendment after allowance to modify the claim and address the examiner's concerns.

Amendments after allowance can address various matters, such as changes to the specification or claims, modifications to the drawings or list of inventors, and the submission of prior art. However, the entry of any amendment is at the discretion of the patent examiner, and amendments of greater significance require approval from the supervisory examiner.

Other types of amendments related to patent applications include:

• Amendment after appeal: An amendment made after an appeal is taken from a patent application's final rejection.
• Amendment after final action: An amendment made after final rejection of the patent application.
• Amendment after payment of issue fee: An amendment made by the applicant after the application has been allowed and the issue fee paid.
• Preliminary amendment: An amendment filed before the U.S. Patent and Trademark Office issues an office action on a patent application.

Overall, amendments after allowance are a way for patent applicants to address concerns raised by examiners and improve the chances of their patent application being approved.