The button Check-In you find in each list view of BwPostman. With this button you may check-in entries that are orphaned. You recognise these entries at the lock symbol at the beginning of a row.
Not all entries, that show a lock symbol, are orphaned! Rather in the contrary. The lock symbol shows, that an entry is edited. The entry indeed becomes an orphan, if you don't leave editing of the entry by buttons but closing the browser or tab, the browser or pc crashes or something else.
To check-in tick the checkbox with the lock symbol and click to the button Check-In. To check-in you need administration rights.