Assuming that you are displaying centerlines in your plan view, displaying them in the sections should be fairly easy. First select the section/elevation that you want to update to show the centerlines -> Right Click on the section and select Regenerate. In the Display Set section, change the display set from Section_Elev to whichever display set you are using for the plan view (for example MEP Design - Plan) and select Ok.
The section should now include the centerline but it may not look like a centerline depending on a setting in the section style. By default, a section doesn't maintain the color and linetypes of the plan objects but you can turn that option on by editting the style of the section and turning On (checking the box) for Maintain layer, color, linetype, etc in the Design Rules tab.
Hope that this helps