I wann reduce my teeth size......front 4 teeths r big........is it possible....?

Ask your dentist: Large straight front teeth in the right location within the face usually look the best. When a patient complains about their "four" front teeth it. Is normally the position of the next two teeth posteriorly on each side that leads to the complaint. The front four teeth need to be within a wide broad smile to be appreciated . Ask your orthodontist.

It may be possible: It is possible to do by enamel plasty. That is removing a small amount of enamel from the tooth. If more enamel is required to achieve the cosmetic result you desire you may require veneers to achieve the best end result. In my office I use a black sharpie pen to black out the enamel i want to remove. This will give you some idea of the end result that is completely reversible.