Assuming you have a Word document saved with addresses in table cells of a
specific Avery type - Open the document, click "Tools", "Letters and
Mailings" (or Envelopes and Labels in an earlier version), "Envelopes and
Labels", click the "Labels" TAB (should already be clicked), click the
"Options" button, select your new label type, click "New Document". Your
document labels will change to the new format. If you want to overwrite the
previous label format, you will need to switch over and close out the
original, then save this new one with the same name and folder as the
original.