Reverse charge

It depends on the type of service supplied.

let's assume it's a a kind of technical service. whether RCM will still apply?

No. RCM is not applicable.
As per notification no. 13/2017 dated 28.06.2017, the govt. has notified the following services taxable under RCM:
Supply of services by:
1. a GTA
2. an individual advocate including a senior advocate or firm of advocates
3. an arbitral tribunal
4. any person by way of sponsorship to any body corporate or partnership firm
5. CG/SG/UT/LA (subject to few exceptions)
6. a director of a company to the said company
7. an insurance agent
8. a recovery agent to a baking company or a financial institution or NBFC
9. an author, music composer, photographer, artist or the like to a publisher, music company, producer or the like.

Since supply of technical services is not provided in the above notification, it is taxable under forward charge.