A P11D override allows you to enter manual adjustments to values on an employee's P11D. From Sage 50 P11D v28 onwards, you can submit forms P11D and P11D(b) to HMRC through your software with overrides in place.
Any values you enter in the P11D Override take priority over calculated benefit values that have an exemption assigned to them.
CAUTION: When you add an override, you must manually check if the Class 1A NI has changed. If it does change, click Employer then Employers P11D (b) Declaration then the Adjustments tab. Adjust your P11D(b) as required before you send your submissions to HMRC.