A grace period refers to a specified number of calendar days following domain registration in which the operation may be reversed and a credit may be issued to a Registrar. The Add Grace Period (AGP) is typically the five-day period following the initial registration of a domain name.

AGP was intended to allow for the no-cost cancellation of domain name registrations resulting from typos and other errors by Registrars and registrants as well as some types of fraudulent registrations.

Currently, when a domain name is registered through a Registrar, that Registrar may delete the domain name at any time during the first five calendar days of the registration or within the first five calendar days of submitting an application for a .aero name (the Add Grace Period or AGP), and receive a full credit for the registration fee from the Operator.

Once a domain name is deleted by the registry at this stage, it is immediately available for registration by any registrant through any Registrar.