Select the object, then choose Constrain Remove Constraint from the Constrain panel.
If the object has more than one type of constraint, the status bar prompts you to pick the constraint to remove. If this happens, pick the constraining curve.
In the explorer, select the object's PathCns or TrajectoryCns node (see Finding Path Elements in the Explorer) and press Delete.
If constraints are visible in a viewport (see Viewing Path and Trajectory Information), click the dotted line representing the path or trajectory constraint and press Delete.
Except where otherwise noted, this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License