The very first and important thing you have to do before deleting the application from your device is to save and test your 12 words backup phrase using MEW:
Open Pillar Wallet and go to Settings
2. Click Reveal backup phrase and type in your PIN code
4. Next step is to test this 12 words using MyEtherWallet and see whether you have access to your funds. Here is the the article on how to do that.
If everything works fine - cool, you're ready to delete Pillar application and restore it later. If something went wrong with the steps above - please contact us immediately via in-app help center, website chat box or email ([email protected])
5. Delete the application from your device and install it again on your new/old device via Google Play Store or App Store.
6. Open the wallet and click Restore Wallet
7. Carefully type your 12 words backup phrase using lowercase letters and without any commas (just put a space between the words). Click Restore Wallet afterwards.
8. We're almost there! Click the Next button after Welcome screen.
9. Set your PIN code and remember it in order to avoid restoring your wallet once again using backup phrase :)
That's it, you've successfully restored your wallet!