Vendor Posting profile fields

Hi ,

In Vendor Posting profile we have the fields like cancle , close.

From Help

Cancle : Select this check box if you want to be able to cancel transactions that have this posting profile.

Close : Select a posting profile to change to when transactions that have this posting profile are closed. A transaction is regarded as closed when it has been settled in full.

Could any one explain what is the use of the above fields in real scenerio and expecting the answer with an example.

Thanks in advance.