I need to change a temporary licence file with a permanent one.
as far as we know we have to use license file wizard but I don't know if the new license will be active as soon as we load it or we have to restart the servers (the customer has redundancy)
My friend Brandon is most correct! +5 points here Brandon. I thought that I would just add this link as well :)
Check out Step# 16 below :)
Converting a Cisco Unity Demonstration System to a Standard System
Do the following procedure after you have ordered and received the license file for a standard Cisco Unity system.
Step 1 Log on to Windows by using the Cisco Unity installation account.
Step 2 Exit the Cisco Unity software.
Step 3 Double-click the Cisco Unity Tools Depot icon on the desktop.
Step 4 Under Administration Tools, double-click License File Install Wizard.
Step 5 On the Welcome screen of the wizard, click Next.
Step 6 Click the name of the demonstration license file (CiscoUnity50.lic or the time-limited license file), and click Delete to remove the demonstration license file from the list. (The file will not be deleted from your local system.)
Step 7 Click Add.
Step 8 Insert the Cisco Unity license file disk, if applicable.
(When Cisco Unity was registered on Cisco.com, Cisco replied with an e-mail containing an attached file with licenses for Cisco Unity features. The instructions in the e-mail directed that the attached file be saved.)
Step 9 Browse to drive A or to the location where the license files have been stored.
Step 10 Double-click the license file to add it to the License Files list.
If prompted, click Yes to copy the license file to the local system.
Step 11 If you are adding more than one license file, click Add, and repeat Step 9 and Step 10 for each license file.
Step 12 Click Next.
Step 13 In the Licenses list, confirm that the license information is correct.
Step 14 Click Next.
Step 15 Click Finish.
Step 16 Restart the Cisco Unity server.
Step 17 If you are not adding voice ports, skip to Step 19.
Hope this helps!