How can I make a default font on existing template

Hi all. I am an editor of a monthly newsletter. I have a template that I created and use for each issue. I usually just duplicate the document and erase any old data and add the new to save me time. However, one issue I've been having is a font issue. The default text is Helvetica Neue, but we all prefer Times. I use text boxes to adjust the always changing layout. There are times when I set the text for a box, type a line, hit return and type a new line only to find the font has reverted to Helvetica Neue. This is aside from frustrating as I'm trying to align text but have to stop and keep changing the font back to Times. If I do all the work and then change the entire box to times, my work is all screwed up.

Is there a way to make the text boxes and all the existing font types default to Times? Changing font so regularly is annoying. BTW I'm using OS Sierra and pages 6.3.1 on an 2012 iMac.