There are several methods that you can use to perform a factory reset on your Bluefruit LE module if something gets misconfigured, or to delete persistent changes like UriBeacon or advertising payload changes, etc.
These methods are the same for both UART and SPI versions of Bluefruit LE
If you hold the DFU pin low (set the pin to GND) for >5 seconds, the red and blue LEDs next to the module will start blinking and the device will perform a factory reset as soon as you release the DFU pin (disconnecting it from GND).
If you have a DFU button instead of a pin, just hold the button down.
There is a FactoryReset sample sketch in the Adafruit Bluefruit LE library, which can be access in the File > Examples > Adafruit_BluefruitLE_nRF51 folder (See the Software section of this tutorial for instructions on installing the library):
Upload this sketch and open the Serial Monitor and it should perform a factory reset for you:
You can also perform a factory reset by sending the AT+FACTORYRESET command to your Bluefruit LE module in your favorite terminal emulator or using the ATCommand example sketch.
This command will also cause the device to reset.
On the bottom of the Bluefruit LE Friend board or shields there is a test pad or pin that exposes the Factory Reset pin on the modules (marked FCR or F.RST). Setting this pad low when the device is powered up will cause a factory reset at startup.