In reply to Hocine Tighiouart.

PROC KDE supports the SCORE statement, so you can get the density estimate of CDF (y) at any point (x) that you specify.
To go the other direction is harder and usually requires a formula for the CDF to get accurate quantiles.
If you know the CDF formula, you can use numerical root-finding to find a quantile. If you only know the CDF at a discrete set of points (like on a grid), you have to use interpolation.