A saved mailing list may contain everyone on a project, while one particular draft belongs only to the people attending a workshop. Change the recipients of that draft instead of editing the reusable list for a temporary exception.

First prepare an expected recipient roster for this message. Use complete email addresses, including which address to use for anyone with several contact entries. A correct headcount can conceal one wrong person and one missing person.

Turn the list label into inspectable addresses

Open a new Thunderbird message. Show View, Contacts Sidebar if it is hidden, select the address book containing the list, and locate the intended list. Add it to the recipient field appropriate for the message, such as Bcc where recipients should not see the other addresses.

The inserted list name is a group representation. Right-click it and choose Expand List to expose the individual recipients. You can then remove the person who should not receive this particular message from the draft's recipient area.

Do not use Edit List in the address book for this one-off change. That is a separate operation on the reusable list. If the group itself is permanently wrong, resolve that maintenance issue deliberately after completing the draft review.

Compare identities, not just the total

Review To, Cc and Bcc together. Check every expanded address against the roster, including the domain and any similarly named contacts. Confirm that an excluded person has not also been entered independently in another field.

For example, a workshop roster of four addresses should match those four exact addresses. Seeing four recipient chips is insufficient if one contains an old personal address instead of the approved work address.

Save the message as an unsent draft and reopen it for a final recipient check. Independently open the saved mailing list and verify that its normal membership remains intact. Those two observations distinguish a successful temporary exception from an accidental permanent roster edit.

Keep the draft pending for content and recipient approval. This preparation verifies the intended addressing only; it does not establish delivery, permission for a bulk mailing, or the correctness of every address in the underlying contact database.

Sources: Thunderbird documentation.