It may sound obvious, but you should know to whom you are
talking and the capacity in which they are liable. You should be
aware of the nature of the assets they have to administer, the
amount of the debt due from them and when the charge was raised.
You should also have some idea of what you hope to achieve as a result of the call.
Those expectations may change with the information you are presented with during a conversation to recover the debt. However, sound judgement and experience will help you determine the outcome of the conversation.
Referring to the taxpayer profile ( IHTM38072) before making the call will help you to focus your approach.