Can you setup UART Reception on dsPIC33EP512MU814 on eval board dsPICDEM MCLV-2
From the datasheet (emphasis mine):


  The number of available pins is dependent on the particular device and
  its pin count. Pins that support the Peripheral Pin Select feature
  include the designation “RPn” or “RPIn” in their full pin designation,
  where “RP” designates a remappable function for input or output and
  “RPI” designates a remappable functions for input only, and “n” is the
  remappable pin number.


Since an "RPx" pin can be either input or output, you can remap the UART Rx to it.

RPINR18 = 0x0064;      // UART Rx PPS -&gt; RP100