Because of the protocol implementation on Philips Hue bulbs, it is not possible to remotely factory reset the bulb. Instead a separate Philips Dimmer Switch is required to proceed. 

With the Philips Dimmer Switch in hand, bring it within 10 cm of the bulb or lamp you wish to factory reset, then press and hold the I and 0 buttons simultaneously.

Continue holding for 10 seconds until the green LED illuminates on the dimmer switch, the bulb will flash just before receiving the green LED.  The bulb is now reset and can be re-included.