If your business was previously registered for GST and now are liable for SST, then you will need to create a new SST Tax Authority in Sage 300.
This is because under GST, your business is required to maintain records for at least 7 years.
As such, it’s best to maintain a separate set of records for SST by creating a new Tax Authority so that transactions previously recorded under GST, and current transactions recorded under SST can be easily accessed when needed.
If you are registered for both Sales Tax and Service Tax, then it would also be best to create 2 separate Tax Authorities, one for Sales Tax, and another for Service Tax.
Setting up new Tax Authorities in Sage 300
In Common Services, click on Tax Services, then Tax Authorities.
Enter tax authority name and liability account which is going to be used for Sales transactions.