If you are willing to create or change the exitsing Self Service Instance for SageCRM please have a look at the steps mentioned below.
Steps to create a new virtual directory for self service is given below:
1. Go to Control Panel->Administrative Tools->Internet Information Services
2. Right click on the Default Web Site and select New option.
3. Click on Virtual Directory
4. Using Virtual Directory Wizard you can write your self service instance name and click on Next
5. In the Directory field, you have to select self service path (for example “C:Program FilesSageCRMCRMSelfServiceDemo”).
Now your Virtual directly is created. You can browse the self service application with http://xxx.xxx.xx.xx
HTH.