Civil Litigation

It's not clear who's a defendant and who's a witness here, since you said "named on a complaint" but then you said "named as a witness." It's not clear is anyone's been ordered to appear anywhere. You'll know if you have to appear somewhere and when because you (or your lawyer if you have one) will get served with a Notice to Appear (if you're a party to the lawsuit) or with a Subpoena (if you're a non-party witness). If you don't get served with those documents, you don't have to appear anywhere. If the plaintiff makes someone appear and they've got no knowledge, that's the plaintiff's problem, but whoever is properly served still has to appear.

Disclaimer: Please note that this answer does not constitute legal advice, and should not be relied on, since each state has different laws, each situation is fact specific, and it is impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue. This answer does not create an attorney-client relationship.

You do not state if you are the person "named on the complaint" but if you are, and you do not have legal representation you should seek out an attorney immediately. If you are a named defendant in a lawsuit your legal rights can be affected. It is not wise decision to ignore a lawsuit if you are a defendant, regardless of whether you have been deposed or called as a witness.

Disclaimer: I am not your attorney. This answer does not create an attorney-client relationship. The above does not constitute legal advice. Do not rely on this answer. Each state has different laws and procedural rules and each situation is fact specific. It is impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue.