Hello @Jim Bragg
Based on the information available in the Azure documentation, it appears that the remaining 40 VM reservations would still be considered part of the original RI and would be eligible for one more exchange.
The documentation states that "each reservation can be exchanged once for a new reservation of equal or greater value" and that "reservations purchased before January 1, 2024, can be exchanged for a new reservation of equal or greater value until the end of their term."
Since you have already exchanged 60 of the 100 VM reservations, you would have 40 remaining reservations that are still part of the original RI. As long as you exchange them before the end of their term, you should be able to exchange them for a new reservation of equal or greater value.
However, I would recommend contacting Azure support for more information and clarification on this matter, as they would be able to provide more specific guidance based on your particular situation.
Please accept answer and upvote if the above information is helpful for the benefit of the community.