Query in changing the LastDateOfEmployment in employee table

Question

I need help in writing this SQl query. I'm not good at nested queries.

I have a tblemployee. The business rule is that HR updates LastDateOfEmployment when an employee leaves the org, but also changes his/her reporting employees' managerid to someone else in the org.

The HR updates the LastDateOfEmployement, but takes time to update reporting employees' ManagerID. This is creating a break in an application in .NET (treeview control).

So a workaround our dept is suggesting is the need to write a query to find all managerid from tblemployee and that managerid's LastDateOfEmployment. If the LastDateOfEmployment is not null, update it to null, and there are other stored procedure that takes care of rest.

Please help. This is critical.