Canceled of registration of plot

I want to purchase a plot number 101 in a RERA registered project of some 397 plots. but special case with this plot 101 is that some other person say Piyush has purchased it by mistake after completing registration and agreement, later he realized that he wanted purchase plot 102, and due to some manual mistake in allotment he was allotted with plot 101. He then signed a change deed letter which just says to change plot number 101 to 102, mentioned in document 18045 (102's sales agreement letter) few part of that canceled letter : 65-चुक दुरुस्ती पत्र दस्त क्रमांक 18045 Pune क्र 23 दिनांक 15/10/2019 या दस्तामधील प्लॉट क्र 101 नसून 102 असा आहे ही दुरुस्ती वाचण्यात यावी. Is that enough to change ownership of Piyush from plot 101? Does Piyush not require to cancel the whole registration and changing the ownership to Builder again by paying the same fee as he paid for registration? What things should I take care of before purchasing plot number 101 now, What documents should be in there place before this purchase?