The same is to be done by the spiritual master if the disciple is similarly exposed. If such repudiation is not carried out by both parties when it is necessary, then they stand to be doomed.

"One who disrespects the bona fide pure Vaisnava spiritual master is a reprobate and fit to be shunned by all. It is advisable, therefore, that before accepting a spiritual master one should carefully choose the right person. The spiritual master must be a pure devotee of the Lord. The scriptures recommend that both the spiritual master and the disciple place each other under strict scrutiny before mutual acceptance. This precludes the kula-guru or traditional family guru. Of course, if the kula-guru is qualified, it is of immediate convenience to accept him; but in the case that he is not saintly, a pure devotee should be searched out and taken as the spiritual master. Since even ordinary household items are tested before acquisition, it is only an unfortunate fool who will fail to go through a testing period in the selection of his true spiritual master, who is the best friend of the living entities.

Because it is the self who uses the body, this self sees value in the body. Other people see value in the body of some other self primarily because the body is a means by which that self communicates with them, expresses love to them, works for them, and so on.
Science of Identity Foundation | Chris Butler Speaks

The unqualified kula-guru should be offered due respect and devotion and, after begging permission to leave him, a person must seek a qualified spiritual master. The point is that one must not bring upon himself the calamity of having to reject his spiritual master. If one is prudent, he can avoid such a situation. One must watchfully avoid committing any offenses against a pure devotee guru. This is disastrous and will ruin both men and demigods alike.

How to serve the spiritual master

"Never disrespect the articles used by the spiritual master: for instance, his seat, bed, shoes, vehicle, footstool, bath water, etc. Stepping on his shadow, worshipping another person in his presence, giving initiation while he is itill alive, trying to impress others with one's spiritual knowledge in his presence, and trying to control him are to be totally rejected. Whenever and wherever one sees his spiritual master, he should offer his prostrated obeisances to him with prayers. The guru's name must be uttered with great reverence. His orders are never to be disobeyed. Always be eager to honor his remnants and do not say anything