Guys, would like to ask if I apply for the iValue plan 2 (RM155), can I do some supplementary lines to my family members?

Is there any penalty for terminating my current iValue Plan 2? I have been subscribing this plan since the day iPhone 4 was launched and it's a 24 months contract period. Most likely I think it would have to pay certain amount of penalty charge, but I would like to know how much I should pay and what are the consequences if terminate the plan? Thank you so much.