Here is the basics of how to sharpen a reamer on our Tradesman Machinist
Reamers have circumferential margins
The OD of the reamer is the guide, reamers cut with the leading margin end corner.
If reamer margins are good and the corners are sharp (all the same length) you should get a good hole .
Sharp corners dull quickly this is an easy way to refresh these corners accurately on reamers up to 7/8