Hadith - Reported by Ahmad (3/403) and Ibn Abee 'Aasim (2/521) with a saheeh isnaad.
It is authentically reported from the Messenger in the hadeeth of 'Iyaad ibn Ghunum who said, "The Messenger of Allaah (saaws) said, 'Whoever desires to advise the one with authority then he should not do so openly, rather he should take him by the hand and take him into seclusion (and then advise him). And if he accepts (the advice) from him then (he has achieved his objective) and if not, then he has fulfilled that which was a duty upon him.' "
Source : SF
It is authentically reported from the Messenger in the hadeeth of 'Iyaad ibn Ghunum who said, "The Messenger of Allaah (saaws) said, 'Whoever desires to advise the one with authority then he should not do so openly, rather he should take him by the hand and take him into seclusion (and then advise him). And if he accepts (the advice) from him then (he has achieved his objective) and if not, then he has fulfilled that which was a duty upon him.' "
Source : SF