In full version you have to do the RE again, compare two models and generate alter script for them.
In Beta 18.104.22.168 it is not necessary. You simply open the Sync & Convert Wizard from the updated model and on page Select Right Side of the wizard, via the Reverse Engineering Alias box you can connect to your db directly. So, prior RE is not necessary.
Unfortunately, Beta 22.214.171.124 expires on 1 February and therefore the Beta download link was disabled. Another Beta is not available at the moment, we are working on it. So, you will be able to check out this feature when the new Beta is released, which can be in a week or two.
Thanks for your patience.
In any case, forward engineering is not supported in TDM. So, you need to use a third party software to run the generated alter script in database. If you use Oracle db, you can use Toad for Oracle that is integrated with TDM. (Please see Settings | Options | Toad for Oracle Integration.) You can also select Toad for Oracle as a default editor to open every generated SQL script in Toad for Oracle. (See the Help file for more information.)