How do you withdraw a subpoena that's already been served?

I agree. However, in addition to personally speaking with them, make sure that you also send them something in writing. That way there is no confusion and if, for some reason, they forget and do show up, you want something to show to the court that you actually did contact them. Good luck! Legal Disclaimer: You should remember that this answer does not constitute legal advice, and should not be relied on. This is because each state has different laws and each situation is fact specific. That is why a lawyer can't evaluate a legal problem without a consultation and a chance to review every fact and document at issue. Also, this answer does not create an attorney-client relationship between us.

Call them all and tell them and/or write correspondence to them. This happens to litigation attorneys frequently. In fact it just happened to me yesterday and we made certain we spoke to the witnesses directly so that they would not waste their time, miss work and then be agitated with my office. This answer is provided for informational purposes only. Actual legal advice can only be provided in an office consultation by an attorney licensed in your jurisdiction, with experience in the area of law in which your concern lies.

I agree, call the witness immediately and let them know the matter is no longer being heard. This will put your office in the best light with the witness and the Court. If there is a new date, you will have to issue another subpoena. Disclaimer: This answer does not establish an attorney-client relationship and does not constitute legal advice. It is for general informational purposes only.