How to display nothing (blank soace) in the place of Null values (‘Phi’ symbol)

[NIX]

I want to display Null values as empty cell values, how can I acheive that.
I neither want a Phi symbol nor 0 displayed in the table as shown in the picture below.

As in the picture displayed above, it should be just a blank space, instead of NULL. The value above are genererated using a pivot.