Follow below mentioned steps to disconnect the domain from the site:
step 1 : Login into your Appy Pie account
step 2 : Go to My Domains
step 3 : Click on the dropdown menu of your domain name
step 4 : Click on Disconnect
step 5 : A popup window, asking your confirmation to disconnect the domain, will appear, click on Disconnect
step 6 : That’s it! Your domain will be disconnected from the site.