How to apply a Dimension Style to dimensions that are existing in a drawing, but have no associated Dimension Style
If you want to update dimensions in an existing drawing, and have these dimensions display with the same size, font, layout etc. etc., it can be achieved by creating a Dimension Style and then applying that Style to the existing dimensions. This can be useful when the drawing(s) contain(s) many dimensions.
This should change all dimensions in the model to the new Dimension Style.
Image 1 - Expand Element Selection tool
Image 2 - Element Class tab
Image 3 - Change Dimension tool