Deleting the Registration of the Runtime
Library: -r 
Use the option –r to delete the registration of a runtime library of the interface programs on the client. Specify the path in which the client installation is located.

irconf -r -p /opt/sapdb/interfaces/precompiler/runtime/7.2
You see a message about the deletion of the registration, including the path and the version of the runtime library of the interface programs.

/opt/sapdb/interfaces/precompiler/runtime/7401 -> 7.4.01.00 registration removed