You will need to manually raise a rent demand specifying with the end date of the period, this will ensure that the next Rent Period commences on the following day.
To do this, go to the tenancy record and scroll down to Rent Schedule. Click on Demand Next Rent.
On the following screen change the Rent Period End Date to the day before the next rent due date. If the tenant wishes to pay rent on the 1st of the month, select the last day of the month. This will apportion the rent and the new calculated rent amount will be shown, then click save.
If you return to the Rent Schedule Section you will see that the Next Rent Due date has now updated and the next rent demand will be raised on the 1st as requested.