The general instructions are to use the ActivationTool (usually found in the application's installation directory) to re-activate the product using the proper activation key, hardware fingerprint, and host ID. Note that if you're re-activating from the same computer that the software is installed on, then there's an option to "activate this computer" as opposed to "activate another computer" where you will then need to manually specify the fingerprint and host ID.

Once the new license file is downloaded, replace the old license with the new license and then restart the relevant application or service.

The license file for Forms goes into the <Laserfiche Forms installation directory>\Forms\bin folder. By default, this would be C:\Program Files\Laserfiche\Laserfiche Forms\Forms\bin.