According to your question you probably mean to ask that you have qualified for jee advanced and what if you don't write jee advanced? So I would like to tell you that you will not get an opportunity to apply/take admission in institutions which are asking for jee advanced scores like iit's this is the the only problem you will face other wise you will be able to get admission in all institutions asking for jee main scores like nit/iiit/gfti you may participate in josaa counselling for the same.