Auditor in corrective action

Hello everyone,

As the inspection process is done, we are asked for the corrective action:

So if we ticked this checkbox and save it, It will automatically open the corrective action window.
In that form, the last information they ask about is of the auditor as shown below

For now every employee can be the auditor.
My question is how can we define specific people as an auditor.

Any help would be great.

Thanks in advance,