I hope you don’t mind a little criticism with the intention of being constructive…
Personally, I’m not a big fan of such “preapring for an audit” type SOP. It implies that the doc control system is not set up to already support the audit. To me, your quality system ought to be exactly aligned with the way you work and vice versa. If not, you have underlying issues that need to be addressed. About the only thing I see that is ‘reasonable’ in preparing for the audit would be to ensure the facilities are properly reserved.
The SOP also lost its focus (per the title) and got into what to do DURING an audit. There’s certainly some good info there (e.g., to always accompany an inspector). You might also want to consider how to handle distributing records / docs and what is out of scope. Some companies always stamp “COPY” on the cover of materials provided to the inspectors. Some only hand over electronic copy. There’s no right answer but I’ve seen it be helpful to standardize. Also, if it’s an FDA audit, Management Reviews are not required to be shown the auditor. You can certify that they are being held according to the procedures.
Finally, the SOP talks about what an auditor should or should not do. That’s really up to them and is, IMO, irrelevant to the SOP. You are welcome to ask for credentials and you should find out about the findings escalation process if you cannot resolve issues the auditor raised. But you can’t really control if and how far in advance you are notified of an upcoming audit or how an inspector handles findings.
Hope that’s helpful.