You can create what we call draft pull request, they can't be merge and the code owners doens't need to review it.
The CODEOWNERS file (inside the root folder , .github or docs folder) permits you to assign people to certain part of the repository, such that when a change is made, they are directly assign to check and validate it!
/code/apache @apachegohst
Open, Draft, Merged, Change and Review required,Qpprove, Conflict, Ready for review!
You can make a commment to review a PR, you can also add review at certain ligne of code