Partial reverse charge: provider exempt under SSI does not pay; service receiver still liable for receiver's portion of tax.
Where a service falls under partial reverse charge and the provider is covered by the SSI exemption and not liable to pay service tax, the provider's obligation to pay its share is eliminated while the service receiver remains independently liable to pay the receiver's portion under the reverse charge mechanism.

Reverse charge liability now places full service tax responsibility on the service recipient for manpower and security services.
W.e.f. notification no. 07/2015-ST the services by way of supply of manpower for any purpose and security services have been placed under a full reverse charge mechanism, making the service recipient exclusively liable to discharge the entire service tax; the earlier partial reverse charge split between recipient and service provider has been removed.

Partial reverse charge: service tax liability split between provider and recipient; third-party payers allowed under notification
A scheme of partial reverse charge allocates service tax between provider and recipient by notifying services and the share payable by the recipient, the provider paying the remainder. As at 01/04/2015 the notification covers renting of passenger motor vehicles to persons not in the same business and the service portion of works contracts. The framework also allows liability to be placed on persons other than provider or recipient, for example a representative of an aggregator, where so notified.

Aggregator liability: platform owners bear service tax responsibility, with representatives appointed if no taxable territory presence.
An "aggregator" is the owner manager of a web based application enabling customers to connect with service providers under the aggregator's brand; the aggregator is the person liable for paying service tax for services involving the aggregator. If the aggregator lacks physical presence in the taxable territory, a person representing the aggregator in that territory is liable; if there is neither presence nor representative, the aggregator must appoint a person in the territory who will be liable to pay service tax.