When you select an Owner and Reviewers for an approval unit and its parents, you set the approval unit promotional path.
After the review process has started for the Scenario, Year and Period for the approval unit, the approval status is "Under Review" for the entity, and a current Owner is assigned to the entity according to the promotional path defined for the approval unit hierarchy.
At this stage, only the current Owner of the approval unit with Write access can enter or modify data for the entity.
However, anyone either in the promotional path or outside of it with Read or Write access can view the data.
The current Owner of the approval unit changes as the entity is promoted within the promotional path. After an entity has been promoted to the next level, you no longer have Write access to the data, although you continue to have Read access to the entity's data.