Pope Cannot Change Church Teaching

Not at all. He cannot teach that as the successor of St. Peter. Rather, what he has been teaching is that there are certain concrete cases that might permit divorced and remarried persons to receive Holy Communion because of some aspect that removes their culpability for their situation. These cases would be so particular that they would have to be described in detail. One cannot generalize about them.

He has made it reasonably clear that these cases have to be dealt with one by one. There is no, and there can be no, general permission such as you describe. Many bishops and theologians are not happy with the confusion that has been caused on these points recently, and we should all pray that this confusion is cleared up for the good of the souls who are being misled.