If a taxpayer or agent has been told that default of an arrangement/agreement will result in certain action it is important that you review that agreement on time and take the action you said would follow quickly should default occur. For example, if the taxpayer agreed, after negotiation, to discharge their debt in two instalments over the next two months and they default on the first instalment you should issue a Notice of Determination ( IHTM38281) to commence more formal recovery proceedings immediately the first instalment is missed.