In order to hard reset a Samsung Galaxy S Blaze 4G T769, you should perform the following steps.

Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
Samsung Galaxy S Blaze 4G T769 device will be brought back to the default configuration of a brand new device.

1. Power down the phone.

2. Press'n'hold the Volume & Power buttons. Let go of Power button when the phone vibrates.

3. Recovery menu will appear on-screen. From it, select wipe data/factory reset.

4. Select Yes and then Reboot system now.