Descent below levels specified in a STAR
To quote from ICAO D4444 Chap 6-5
6.5.2.4 DESCENT BELOW LEVELS SPECIFIED IN A STAR
Note.— See also 11.4.2.6.2.5.
When an arriving aircraft on a STAR is cleared to descend to a level lower than the level or the level(s) specified in a STAR, the aircraft shall follow the published vertical profile of a STAR, unless such restrictions are explicitly cancelled by ATC. Published minimum levels based on terrain clearance shall always be applied.