If you have the "Tariff-1 (Free)" plan, you can switch to data billing within the list of your OneBoxes. Please contact your manager, and they will upgrade your tariff.
If you have a cloud-based package tariff with per-user payment and you want to upgrade, contact your manager, and they will upgrade your tariff and adjust the billing date.
If you have a cloud-based package tariff with per-user payment and you want to downgrade, contact your manager, and they will downgrade your tariff and reset the billing date (with a downgrade, any prepaid days will be forfeited).