You can quickly produce a list of contacts who have left, using a filter:
Click Contacts and then click Filter
Under Categories column, click Has Left
Under the Available column, select Yes
Click the green right arrow (
) to move the field to Selected column
The list now only shows those contacts who are marked as Has Left
You can now select those you want to add to a tag file (or tick the Select All box)
Please follow these steps to add the selected records to a tag file.