Deleting Applications
You can delete applications youve installed from the App Store. If you delete an application, data associated with the application will no longer be available to iPhone, even if you reinstall the application.
You can reinstall any application and any associated data from your iTunes library as long as you backed up the application by syncing it to your computer. If you try to delete an application that hasnt been backed up to your computer, an alert appears.
Delete an App Store application:
Touch and hold any application icon on the Home screen until the icons start to wiggle.
Tap in the corner of the application you want to delete.
Tap Delete, then press the Home button to save your arrangement.
To overwrite the data associated with an application, use Erase All Content and Settings in iPhone settings. See Resetting iPhone.