Yes, it is possible to repoint over old pointing. Repointing involves removing the old mortar from between the bricks or stones and replacing it with new mortar. In some cases, the old mortar may need to be removed completely before new the mortar mix can be applied. However, in other cases, it may be possible to apply new mortar over the old pointing if it is in good condition and has not deteriorated too much. It is important to assess the condition of the old pointing and determine the appropriate method for repointing to ensure the longevity and stability of the structure.