On the Home tab, under Your craftspace, navigate to Repositories.
Select a repository.
Under Code on the repository page, go to Pull requests.
Select a pull request.
In the Reviewers field on the right-hand panel, assign them in one of the following ways:
Click the search bar and select a reviewer from the organization members in the pop-up list. Alternatively, you can start typing an organization member's name or username and use auto-completion.
To assign a reviewer automatically, click Auto assign.