Macro to change all borders in a range of cells

I need a macro that will change the colour only of cells in multiple tables. The style needs to remain the same. An example would be double line outline, single line vertical and dotted line horizontal. Those styles already exist, I just want to change the colour. I have the following but it changes all borders to single line. It also has to change only borders that are not blank. Some sort of if statement is required, but so far I haven't found the right combination.

Thanks