Autodesk CIVIL3D - CIVILDESIGNCOMP 2007 SLM CD Tutorials Manual page 794

Parent (STA: 0+100) and child (STA: 0+080) label styles
Notice that in the drawing, the STA:0+080 and STA:0+100 label text are
different sizes, and the text and line are aligned differently. A child style
shares its basic properties with the parent style from which it was created.
If a property value changes in the parent style, then the change is also
applied to the child style. If a property value changes in the child style,
the parent style is not affected.
By creating a child style, you have created the station display you need,
without affecting other parts of the drawing. If you had instead changed
the properties of the parent style, it would have automatically changed
the appearance of any other major stations using that style.
Next, you will set the parent style to override the text setting in the child
style.
Override the child label style
1 In Toolspace, on the Settings tab, expand the Alignment
Station
2 Right-click Perpendicular With Line. Click Edit.
3 In the Label Style Composer dialog box, click the Summary tab.
4 Expand the Component 1 property.
782 | Chapter 19 Labels and Tables Tutorials
Major Station collections.
Label Styles