2 years and a half years later, (February 2019), do check if the new button “Re-request review” would help.
As illustrated on twitter, if your PR was already reviewed, but now it’s time for round 2: With fresh eyes and fresh code, re-request a review 🔃
Note/caveat: (from “Requesting a pull request review“)
Pull request authors can’t request reviews unless they are either a repository owner or collaborator with write access to the repository.
As noted in the comments by gertvdijk:
I am a contributor on the project and the owner of the PR.
It does not make sense to me that I need to be a collaborator on the project to request a re-review?
Oh, wow, it’s by design that PR authors can’t use this feature?
Damn, that’s very much killing the whole feature.