How to delete and reinstall DejaOffice for iOS

1. Touch and hold DejaOffice on the Home screen until the icon start to wiggle.
2. Tap the "x" in the corner of DejaOffice.
3. Tap Delete to remove the app and all of its data from your iPhone/iPad.
4. Click the Home button to cancel or stop deleting apps.
5. Open the App Store on iPhone/iPad and search for DejaOffice.
6. Tap Install. If prompted, enter your iTunes Store account information.

http://www.apple.com/support/iphone/assistant/application/#section_5