We were developing a new feature and on the code complete day, I had to take leave. While code review one of the devs changed my code without proper analysis.
End Result, half the things cannot be tested until that piece of code is fixed

Usually a reviewer should not change code, and if, as in this case, the original dev does not have the time or opportunity to fix it, a second reviewer should look at the changes so that all code gets a review.

Otherwise you defeat the purpose of the review.