Recently I was looking on the web for a way to flip an arrowhead of a dimension and found this blog posting on JTB World. Apparently a command for this has been out since AutoCAD 2006, but there isn’t much documentation on it.
So you have a dimension and you want to flip it’s arrowheads…
Type the command AIDIMFLIPARROW on the command line and select a dimension near the arrowhead you want to flip (it allows you to flip only one at a time).
Hit enter after you make your selection and the arrowhead you clicked nearest to will flip.
Do the same for the other arrowhead if you want.
The final result with both arrowheads flipped: