First of all when is ur sem starting. has it been already started or will it start from march?

if it has already been started like in jan ... than u can only drop the class but can not add the class. if u drop the class than u will have 10 credit as u mention earlier tht u have 14 credit rite now... u can go to international office and talk with international advisor about why u cannot take 14 credit right now.

if ur class is starting from march than u surly can drop or add the class before the class start. if it says u r not elligble than there might be a reason. like the class one u want to take need pre requisist or special permission from the head of the dept or the prof who teaches it.