Once an application for the grant of a patent is filed, it is examined for compliance with the formalities and patentability provided for in the Patent Law. The Patent Office may require the modifications that are necessary to bring the application into conformity with the law. In the event that the applicant does not comply with the requirements of the Patent Office within a given grace period as authorized by the Registrar, a patent application will be treated as waived. Patent applications are carefully examined for the content and novelty of the invention. Once an application is accepted, the grant decision will be published, after which the corresponding patent letters will be issued. Patent letters take at least 2 to 3 years to issue after the usual acceptance process, and this involves additional costs for the applicant. Annuities must be paid each year on the anniversary date of completing the corresponding file at the Patent Office with the required documents. However, payment of annuities cannot be made to the Patent Office, except after the patent is granted.