Budget pool - employee becomes ineligible if promotion completed

Summary:

We are using budget pools for the first time and planning to do this using manager-level budgeting but we want the budget pool to be reduced if a manager enters a promotion for any employee. So if they are promoting someone their budget pool gets reduced. Is there any way to do this automatically and dynamically as the plan is being used?

Content (required):

We are using budget pools for the first time and planning to do this using manager-level budgeting but we want the budget pool to be reduced if a manager enters a promotion for any employee. So if they are promoting someone their budget pool gets reduced. Is there any way to do this automatically and dynamically as the plan is being used?