Add a new expression: dimensionality(). This will show you the various dimensionsionalities in your table. Notice the dimensionality of your chosen text. Then go into your chosen expression, that you want to be bold, and go into its text color properties by clicking on the expand button next to it, under that you will see text color, choose that).
Type in: if(dimensionality()=0(or whatever for your table),'<B>').
Then you are done.
Let me know if you have any problems!
Tried Tibor approach but can't make it work. Dimensionality returned 1, I tried the formula as suggested in both "Text Color" and "Text Format"but the label does not bold.
Regarding Massimo's approach, I forgot to mention this is a Horizontal table, therefore the expressions are the rows titles and the dates are the columns. Massimo's approach works to bold specific dates.
I want the "PD 30+ Days + Current NA" to show bold.