You may clear aircraft to maintain “VFR conditions” if one of the following conditions exists:
The pilot of an aircraft on an IFR flight plan requests a VFR climb/descent.
TERMINAL. The clearance will result in noise abatement benefits where part of the IFR departure route does not conform to an FAA approved noise abatement route or altitude.
MAINTAIN VFR CONDITIONS.
MAINTAIN VFR CONDITIONS UNTIL (time or fix).
MAINTAIN VFR CONDITIONS ABOVE/BELOW (altitude).
and if required,
BETWEEN (altitude) AND (altitude)
When, in your judgment, there is reason to believe that flight in VFR conditions may become impractical, issue an alternative clearance which will ensure separation from all other aircraft for which you have separation responsibility.