In the event of the breakdown of a union, spouses will be considered to be de facto separated when the separation has lasted at least 90 days. Wait until that period has passed before declaring your new conjugal status.
Example
If the separation occurred on 6 January, wait until 6 April, or 90 days later, before informing us of the change in conjugal status. The Family Allowance payments will be adjusted retroactively to February and paid to the person or persons who provide for the care and education of the child.