In order to change ASP.Net version for a domain from IIS one need to perform below mentioned steps:
1) Open IIS Manager.
2) Click on Websites.
3) Right click on domain name for which one need to change the ASP.Net version.
4) Click on Properties.
5) Select ASP.Net tab.
6) Select the ASP.Net version from drop down menu.
7) Click on Apply and Ok.