Yes, we can change security for many Appian objects at once using the Security Summary within an application.

The Security Summary allows you to view the security of all objects within an application in a single place. You can view an application's Security Summary by selecting Security Summary in the Application settings menu .

The Security Summary is helpful when:

1. Viewing the security of more than one object in an application at a time, or viewing the security of specific object types in an application (for example: all process models, or all sites)
2. Finding all objects with missing security (for example: objects with security warnings)
3. Editing security or addressing security warnings in bulk
4. Reviewing the security of all objects within an application or package before deploying it