This particular process cannot normally be done until the extension entry has been created. If using automatic extension creation (the default), this means that license reservation cannot be done until after initial installation of the phone. However, consideration should be given to using this setting with any existing phones already installed in order to ensure that they retain their licenses if possible following the addition of other phones.

Licenses are normally automatically assigned to extensions in order of registration. However existing extensions can reserve a license in order to ensure they do not become unlicensed when new extensions added to the system manage to register first following a system reboot.

• On system's using WebLM licensing, this option is fixed to reserve a license.

• License reservation is not supported on subscription mode systems.