To manage Tasks for other people in such a way that Reclaim is blocking out time on their calendar, you would need them to also sign up for Reclaim and then all of you would need to integrate with a compatible project management system. Currently the ones that support assignment workflows are:

If you are using one of those tools with your team and everyone has the integration enabled in Reclaim, when something is assigned to a team member and the necessary preconditions are met (ex: due date, time estimate, etc), Reclaim will schedule time on the assignees calendar.