I am away from the studio this weekend, and the contest will be in judging mode when I return on Monday. You can allow one designer to make changes at a time in Judging, by rotating the top ranked desiner. The top ranked designer is the only one permitted to make changes. You can rotate the ranking to allow final changes by each designer one at a time.
If you feel that my design is in contention with the requests made, simply rank it No. 1 temporarily to allow the changes, and then rerank for whatever final order you choose.