If you are the successful bidder at auction when the hammer falls and the reserve has been met, you are committed to the purchase!
Normally, the successful bidder will be required to sign the contract upon the auction finalising and pay the deposit. An exchange of contracts then takes place. Any agreed amendments to the contract (note these need to be agreed to in writing by the seller prior to the auction commencing) will be made by the auctioneer before signing. The auctioneer is authorised to sign on any party’s behalf and there is no cooling-off period.