...
To add or remove shading attributes on an Hypershade surface shader node, that shader must be displayed in the Attribute Editor. In the Attribute Editor’s Attributes menu, a 3Delight Shading Attributes submenu will list the available category of attributes. The list of modifiers varies based on the type of the node begin displayed in the Attribute Editor; only relevant attributes are listed.
...
The following attributes are offered for surface shaders that support reflections:
Max Distance
The maximum distance to search for reflections. Using a value that excludes large portions of the scene that cannot be reflected anyway will improve rendering speed.
Samples
Number of samples for the reflection. Higher sample counts produce smoother reflections.
Blur
Angle in radians that define defines a sampling cone. Larger values produce smoother results reflections but may require a higher number of samples.
Noise Amplitude
Amplitude of noise applied to the reflection.
Noise Frequency
Frequency Amplitude and frequency of noise applied to the reflection.