Change IIS port 80 to 81

#1. In Start menu Search option, type: IIS and click Internet Information Services Manager or simply do a run command: inetmgr .
#2. Under Connections, You’ll see your PC name click on it to expand the list. Now you can see “Sites” click on it to expand.
#3. Under Sites you can see Default Web Site, right click on it and Select EDIT BINDINGS.
#4. Edit HTTP binding port from 80 to 81.
#5. Open your browser and type: //localhost:81/yoursite. You should be able to access your local sites without any problems.