Hello @adityacs95,
You should be able to change the license from evaluation to final without needing to set up the cluster again. If you cannot apply the license to the same serial number (in the registering process, you should be asked on which serial you like to apply the license to), change the hardware id of the eval license at the support portal before registering the final license. That will create a new serial number and should change the cluster's serial number after applying the license there. But you won't need to setup the whole system again.
Probably, your Fortinet Partner might be able to guide you through the process as soon as you are there.
Best,
Christian