Your info has been very confusing.

If you have Partners in an entity and you are asking about the activities related to this entity, then there is no Owner, for the LLC, and there is never a SSN. Let's review:

Your client(s) was hired and paid by someone; that work meets the 1099-Misc reporting requirements. That means whoever gave that W9 either did it wrong, or was hired individually and not through their LLC.

Your client(s) had work performed by others or paid for business expense or expenditures that meet the 1099-Misc reporting requirements, and if the LLC hired and paid and is the entity benefiting from that expense, then the LLC issues the 1099-Misc and the LLC is the reporting entity and the LLC uses its FEIN on the form.

Only Humans can have a Social Security Number. The multi-partner LLC is not a Human.

Now you have to figure out what activity happened and who it belongs to. And whose tax return you are preparing and whose tax forms you are responsible for.

You cannot change the info on a 1099-Misc when you are not the responsible party. Your client would notify this issuer that the entity info is Wrong. 1099-Misc can be corrected and reissued. You have the same opportunity, to fix anything you issued that was wrong.