A worker can't add extra bank holidays to a calendar year after that year’s been activated in the admin tool, so please double-check all dates beforehand.
If a calendar’s already active and new bank holiday dates are needed, resolving it would be a chargeable item since it requires providing a new stored procedure, called p_sf_add_bank_holiday, to handle the additional dates.
Please raise a new case online and reference the title of this article.