Schedule feeds pull show dates from an outside source (a booking agency's feed, an iCal link, a JSON endpoint or a webhook) into a tour. Set them up in Tour Settings (or Money), under Schedule feeds.
NOTHING CHANGES WITHOUT YOU: each feed checks in on its own interval and sends what it found to the To review list in Agency Sync (Tour Settings, Agency Sync), the same list your booking agency's dates go to. New, changed and dropped dates wait there, each marked with the feed it came from. Add puts a date on the tour (a show you already entered by hand is matched, not doubled, and keeps its money), Ignore skips it, and Remove takes a dropped date off the tour, asking again if the show has money on it. A date the feed stops listing is only flagged, never deleted on its own. Untick Pending shows or Hold shows on a feed to keep those out of the list; released dates are skipped.
LINKS: paste a calendar's subscribe link as it comes, including webcal:// links.
WHO CAN DO IT: the TM and admins. If you can't see Schedule feeds, ask your TM.