A worked example
Say you add a Damaged item topic and a procedure for broken or damaged items whose steps tag damaged-item and assign the Claims team. Run it on open conversations with that topic, and the ones already waiting get the tag and the team, while no customer gets a surprise email.
Conditions are checked again as each conversation is processed, so the final count can differ from the preview, which stays valid for an hour. Delays don't apply: a procedure set to wait acts at once, since these conversations are already older than any delay. Afterwards the procedure shows when it last ran on existing conversations and how many it changed, and each conversation's timeline marks the run.
Bulk actions for a hand-picked set
To pick conversations yourself, select up to 200 in the inbox and close, assign, snooze, set priority, mark as spam, trash or return them to Aide in one step. Any that couldn't be changed are listed. To tag a set picked by filters, run a procedure on existing conversations. For receipts and newsletters, sender rules file them before anyone has to.