For obvious reasons, any request to backdate a document for these reasons should be flatly turned down.
However, an explanation often given by the person wanting to backdate the document is that the document is merely meant to reflect an oral agreement that has already been made and that this is just a way of documenting it.
The event did not happen during the time period required for the benefit so an attempt is being made to pretend that it did.
This is a fraud on the tax authorities, a criminal offence and is likely to get the lawyer who prepared the document disciplined by his regulator and possibly also charged as a co-conspirator.
For example, if a seller had sold his house in December then the seller could have taken advantage of certain tax benefits.
The thing I liked about the Journal's treatment of the Alexander case was how the reporter managed to be respectful toward the Namibian legal system while at the same time hinting to readers that not every society has the same attitude toward Option backdating scandals: how management accountants can help: backdating of employee stock options can have a significant negative effect on a public company.
Sometimes certain claims (such as insurance claims) can be backdated if the could not be completed at an earlier date, although there must be good reason for neglecting to claim in advance.
If your backdated claim is approved, you will be able to receive benefits from a certain date in the past.
In this situation, it may be possible to create a document after the event which recites what actually happened, and which records the key terms of the transaction.
The document should be dated when it is actually signed, but it can refer to the historic effective date of the transaction.