Can BetBuilder (OBB) selections be cancelled?

Yes, Oddin BetBuilder selections can be cancelled/voided by us. An OBB selection is a unique session constructed from several connected parts (e.g., 'Player A gets over 15.5 kills' AND 'Team B wins the first map'). The odds are calculated based on the correlation between all these parts happening together. If one of these parts has to be voided (for instance, a map isn't played), we can't simply remove it and recalculate the odds for the remaining parts. Because the odds are so closely linked, the only fair solution is to void the entire OBB selection. So, your system should be built to expect that an OBB selection might be voided, and it should handle that status correctly (e.g., by voiding that leg of the combo bet).