1. Tap and hold the app to uninstall it. You will see all app icons start to shake. 
2. Tap ‘X’ in the corner of the app. 
3. Tap ‘Delete’. 
4. Press your device's ‘Home’ button to re-lock your screen. 
5. Launch the ‘App Store’ app. 
6. Tap your photo to launch your account. 
7. Tap ‘Purchased’. 
8. Search for the app and tap to install it.