The association president of a G+3 commercial building is facing a dispute regarding terrace rights. The builder granted exclusive rights to the 2nd-floor owner, excluding common areas like the water tank and lift room. However, the 2nd-floor owner has begun constructing an office on the terrace, despite the association's objections. The president is seeking advice on how to address this illegal construction, as the undivided rights are tied to the 2nd-floor area and do not include the terrace.