In order to hard reset a Karbonn A12+, you should perform the following steps.
Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
Karbonn A12+ device will be brought back to the default configuration of a brand new device.
1. Switch off the phone.
2. Take out the battery and, after a few seconds, put it back in.
3. Press & hold the Volume Up + Power buttons.
4. Now, you will see a menu. In it, select the wipe data/factory reset option.
5. Press the Power button.
6. You're almost done... select the yes-delete all user data option. Press the Power button to confirm
7. Your phone will now reset and restart. Done! Good job.