To Manage Applications of Subscriptions in Reseller Account, Please follow following steps:-
1) Login to Plesk control panel.
2) Click on "Subscriptinos".
3) Click on "Manage Hosting".
4) Click on "Applications Tab".
5) Click on "Featured Appliaction". By One Click to Install.
6) Click on All Available Applications. To View all Web Applications.
7) Click on Manage Installed Applictions. To Manage Install Web App, i.e. DB, Remove Installed App, Update Other Info and etc.
