Even if the agent does act without authority, the principal may ratify the transaction and accept liability on the transactions as negotiated. This may be express or implied from the principal's behavior, e.g. if the agent has purported to act in a number of situations and the principal has knowingly acquiesced, the failure to notify all concerned of the agent's lack of authority is an implied ratification to those transactions and an implied grant of authority for future transactions of a similar nature.