The way to change the port is to go to the installation directory of the Web Portal that is usually
Run setup.bat (I suggest to right-click the file and run as Administrator)
The Metadata Management (MM) Setup window will come up
The default port of 11680 will be listed.
On the Port Number field, you may change that to be a different port.
Let's say you already have Web Portal installed.
Uncheck Enable Windows Service and press Configure
That will remove the windows service for the Web Portal that is named ERwin Web Portal Application Server
Now go back into the setup.bat and check back on Enable Windows Service
Type the new Port number
Now press Configure
That will install the windows service for the Web Portal that is named ERwin Web Portal Application Server using the port that you desire.
When you access the Web Portal you will need to specify the different port in the URL.
For example, the default URL is http://localhost:11680/MM/
So if you change the port you would instead type,
Where 12345 would be replaced with the new port number that you configured.