A power of attorney holder can only do he is instructed to do.if the PoA holder sells the land to a person to whom you want to sell, the sale deed will contain your name as you are the owner of the property.
It will also contain his name as the PoA holder and signing on your behalf.
I may remind you that the supreme court has deprecated transactions wherein people give PoA so that stamp duty etc.can be avoided.
Development agreements can be made by a person with a builder.
GPA transactions are not transactions or sales as per the supreme court.