Replacing missing values with median

[ozge1]

I have tried to replace all the missing values in my data with the median. 

proc stdize data=callcenter out=callcenternew missing=median;
var _numeric_;
run;

It messed all the numbers that I have in the data. 

How can I replace missing values with the median?

[Tom]

You need to add the REPONLY option if you don't want it to actually standardize your variables.