One way would be to add a switch to your condition in the CF.

For instance:

Define HideZero as True (Insert/Name/Define). Then change the CF to

CF1: Formula is =AND(A1=0,HideZero)
Format1: <font/<backkground color

change HideZero to False (manually or by macro) to show the zero values.

OTOH, if you want to hide ALL zero values, it's probably easier to just
uncheck the Tools/Options/View/Zero Values checkbox.

In article , "PT"
wrote:

I've formatted a number of cells so that their contents "go blank" if the
cell value is zero, but display with their values otherwise. The "blank is
accomplished by setting the font color to "white".

Now is there either a conditional formatting or macro trick which would
enable me to only apply globally the conditional formatting when I want it?

In other words, the cells would normally show zero values, but could be
globally turned "blank" at my command.