You can convert any of the RIAA phono pre-amplifier inputs to line level by removing four jumper sleeves from the channel PCB assembly that you want to convert.
For details please refer to the Installer Link Options* (p.36/37 of the Xone:92 User Guide)
(*other options available are Input Gain Disable, Filter Disable, Midi - Filter 2 only)
As stated in the User Guide:
CAUTION: The following service instructions are for use by qualified personnel only.
To reduce the risk of electric shock do not perform any servicing other than that described in the operating instructions unless you are qualified to do so.
Refer all servicing to qualified service personnel.
Please contact your dealer or local A&H distributor to arrange changes to be made, you may invalidate your warranty if the work is carried out by unqualified service personnel.