For pre-paid customers,The procedure is as follows;
1.Dial *126 #
2.Choose set or change Bonga Pin (Option 6)
3.For set new Pin select 1
4.Enter your National ID Number.
5.Enter your Last Direct Top Up Amount.
6.Enter the Pin you want.
7.Confirm the Pin.
8.Click OK to confirm
To set bonga points for post paid customers;
Dial 200 to talk to safaricom customer care.