changing text size of existing lable of plot line

[rembocanoe66]

I've used AutoCAD since 1985 and CA for the last decade. But I've always been stuck on this one thing.

I understand that I can change the default txt sizes in the default settings. and I can modify the annotations that delineate font characteristics. But when I have an EXISTING line label (in this case a Terrain perimeter indicating the property line)  how do I change the label text heights without redrawing the line?

[rembocanoe66]

This is the distance and bearing label for each leg of the property line