Managers should enable and support teams in doing retrospectives. They can ask and expect teams to improve within the possibilities and constraints of the organization, and contribute to the organization's goals, but it is up to the team to choose how they improve and where they decide not to improve (now).

Should managers attend Scrum?

Daily Scrum

The ScrumMaster should also attend, in the role of coach and facilitator. ... Others might also want to attend the daily scrum—managers, stakeholders, anyone, really, who wants to better understand how the team is progressing toward the sprint goal.

Who should be in retrospectives?

The sprint retrospective is usually the last thing done in a sprint. Many teams will do it immediately after the sprint review. The entire team, including both the ScrumMaster and the product owner should participate. You can schedule a scrum retrospective for up to an hour, which is usually quite sufficient.