Issue description
When attempting to change the reference line of a wall, column, or beam, it is not possible because the reference line is grayed out in the element settings.
Solution
In Archicad, the reference line of a column (or other profile-based elements like walls and beams) cannot be changed directly in the element settings if the element is using a complex profile. Instead, the reference line is determined by the profile origin set in the Profile Manager.
Options > Profiles > Profile Manager...
The profile origin determines the position of the reference line for profile walls, profile beams, and profile columns. The origin of profiles is marked with a small "x" in the Profile Manager. Because of this, the reference line cannot be changed in the element settings.
To adjust the reference line position, the hatch patterns in the profile manager must be repositioned so that the profile origin aligns with the desired reference line location.
Tip: Each profile has only one origin. If multiple reference line positions are needed for a profile, different profiles must be created using the same drawing elements but with different origins.
For further reading How to edit a Profile