Yes, you can apply for RTI application for the status of application and action taken by concerned authority to whom the application for change of the property in RTC.
The Sub registrar office comes under Revenue Department of the States, which is a Public Authority u/s 2 (h) of RTI Act, 2005.
The Revenue Department is responsible for maintenance of record of rights, recovery of land revenue and all other kinds of Government dues.
In the decision of Central Information Commission in the case titled Surender Pal Singh vs SDM (Kanjhawala), GNCTD bearing no. CIC/SA/A/2014/000462, it has been laid down that transparency of land records is the mandate as per the RTI Act and it is the duty of land authorities to provide information about land records to citizens.
Hence, application can be made u/s 2(f), 2(j) and 6 with the payment of requisite fees as per RTI Act, 2005.
To file application for the same please refer: https://onlinerti.com/how-to-file-rti-online-for-karnataka