A salary sacrifice arrangement is an agreement between an employer and an employee to change the terms of the employment contract to reduce the employee’s entitlement to cash pay.This sacrifice of cash entitlement is usually made in return for some form of non-cash benefit.hanging the terms of a salary sacrifice arrangement. If an employee wants to opt in or out of a salary sacrifice arrangement, employers must alter their contract with each change. The employee’s contract must be clear on what their cash and non-cash entitlements are at any given time.