How to control a bit in a register by i2c

Getting a problem.I am making a FM Receiver by RDA5820,Same as TEA5767.But it has 16bit data in a register.All I want just want to change a bit in the register.It seems I can't do this.Need some help

Like this. Reg:A|B|C|D|E|F|G|H Data:0|0|0|0|0|0|0|0

Then change E to 1 I have to write 3E8

Then the FM Channel......Lots of define.

Plz,help

http://www.gammon.com.au/forum/?id=10896