Hello I need an enquiry regarding 3rd round

Hello I need an enquiry regarding 3rd round , I got alloted a seat in 2 nd round which I joined and opted for upgradation in 3 rd round , if I didn’t get any seat from my choices in 3 rd round and if some one with better rank than me filled in choice of my 2 nd round seat will I lose my seat ?

Unless u get upgraded,no one can join your R2 seat

If you don’t get upgraded,how will someone else take your seat??