In many countries, the patent laws allow a procedure for canceling a patent and deleting it. This procedure is a legal procedure that allows any party to request the cancellation or deletion of a registered patent.
In Israel, a person who believes that there was no reason to grant a patent for an invention, may submit to the patent registrar a request to cancel the patent for the following reasons:
1. There is a reason why the registrar was authorized to refuse to accept the patent application.
2. The invention is not a patent.
3. The objectors and not the applicants own the invention.
A patent cancellation procedure can be taken by the owner of a registered patent and also by a person who is not the owner of the patent. The registrar of patents has the authority to cancel a patent at the request of the patent owner himself by virtue of sections 73 and 73a of the law, as well as the authority to cancel a patent at the request of an interested party according to sections 73b to 75 of the law.
In addition, in Israel a court also has the authority to order the cancellation of a patent. This is in the case where the owner of the registered patent leads a claim before the court for the infringement of the patent, and the infringer defends himself in accordance with the defense established in section 182(a) of the law, that is, on the grounds that the patent could have been opposed.
In Europe there is a procedure for canceling or limiting the patent (Limitation and revocation procedure). Pursuant to Article 105A of the Patent Convention, the patent owner can apply for the revocation or limitation of his patent. The patent owner may submit the application at any time after the grant, after the opposition proceedings or even after the patent has expired. However, a request for cancellation or restriction filed while opposition proceedings are pending in respect of the European patent, is considered as if it had not been filed, since the opposition proceedings have priority. In the event that an objection is submitted while a cancellation request is pending, the cancellation procedure will continue for reasons of procedural efficiency. In the event that an objection is filed while restriction procedures are pending, the restriction procedures are terminated and the objection procedures will continue.
In the United States, according to the United States Patent Law, the patent cancellation procedure is called reexamination and it allows any third party to oppose the validity of a patent approved in the Post-grant review or Inter partes review procedure. These two procedures are of the post-grant opposition type.
 The Israeli court has the authority to order the cancellation of a patent by way of indirect attack.
 EPO – European Patent Guide – Chapter 5 – The European patent grant procedure – Limitation and revocation procedure, available at: https://www.epo.org/applying/european/Guide-for-applicants/html/e/ ga_c5_6.html
 Regarding post-grant review, the Patent Law in the United States states:
“Subject to the provisions of this chapter, a person who is not the owner of a patent may file with the Office a petition to institute a post-grant review of the patent. The Director shall establish, by regulation, fees to be paid by the person requesting the review, in such amounts as the Director determines to be reasonable, considering the aggregate costs of the post-grant review” (35 US Code – 321 – Post- grant review).
 Regarding Inter partes review, the Patent Law in the United States states:
“Subject to the provisions of this chapter, a person who is not the owner of a patent may file with the Office a petition to institute an inter partes review of the patent. The Director shall establish, by regulation, fees to be paid by the person requesting the review, in such amounts as the Director determines to be reasonable, considering the aggregate costs of the review” (35 US Code – 311 – Inter partes review).