Other than body corporated, limited companies, private limited companies, if service of rent a cab or Manpower supply is provided by any other individual, partnership firm or LLP, service tax has to be discharged under reverse charge. Under the situation, if a firm has turnover less than or more than 10 lacs, service receiver has to discharge his liability under the provision of section 68(2) of Finance Act. For more clarity, you can refer clause F of rule 2(d) of service tax rules 1994 which is reproduced below:
(F) in relation to services provided or agreed to be provided by way of :-
(a) renting of a motor vehicle designed to carry passengers, to any person who is not engaged in a similar business; or
(b) supply of manpower for any purpose 19[or security services]; or
(c) service portion in execution of a works contract-
by any individual, Hindu Undivided Family or partnership firm, whether registered or not, including association of persons, located in the taxable territory to a business entity registered as a body corporate, located in the taxable territory, both the service provider and the service recipient to the extent notified under sub-section (2) of section 68 of the Act, for each respectively.
I hope the above clarifies both of your query.