If you aren't required to specifically use reduce, compose can be a better way of calling out the parts you want to be "left alone". Only things in parentheses will be evaluated, everything else untouched. So for instance:
append/only saved-data-block compose [contact-name: (get-face contact-name)]
Compose is often the clearest way to express boilerplate with little parts noted that you want to be evaluated. Of course, it's good to understand reduce too.