Availability Control Actions 

When the tolerance limit is exceeded, the system does one of the following:

Warning (Action One)

The system informs you when the tolerance limit is exceeded. You can still execute the business transaction that triggered this (such as posting an FI document).

Warning and Mail to The Project Manager (Action Two)

The system sends the project manager a message containing the WBS element on which the budget was exceeded, and the business transaction triggered the excess.
The amount by which the budget was exceeded and the document number are also specified.

If no manager name is stored in the master record for the project or the WBS element, the system issues an error message instead of a warning and a mail.
For orders, you maintain the budget manager in Customizing, under Controlling ® Internal Orders ® Budgeting and Availability Control ® Maintain Budget Manager.

Warning (Action Three)

The system issues an error message if an action leads to the specified tolerance limit being exceeded. The system rejects the business transaction (such as a purchase order) that causes the budget to be exceeded.