Can i change my choises after appling?

can i change my choises after appling? i mean, can i re-apply to other uni evethough i have already apllied and been acepted? please help me....I'm Italian, I've applied to UWE, Manchester met, Leeds met, Chester uni, UEA, thinking that i wouldn't get enough points to apply to university of higher level but now, that i know what the entry requirements are for Italian students, i'd like to apply to better universities.... do you think i can?