Question: Especially in this age of Kali the fallen souls may commit great offences against devotees of the Lord, knowingly or unknowingly, in their bewildered state.
What happens if they miss the opportunity to rectify their offence by asking the offended Devotee(s) for forgiveness due to that Devotee(s) not being present anymore in this material world?
Answer by Romapada Swami:
Our acaryas describe that the only way to rectify offenses committed against devotees is to seek the forgiveness of that same devotee and render service to them and please them.
If you know you have offended a devotee in the past and they are no longer alive, you can pray to Krsna and beg forgiveness by sincerely repenting for the offenses you may have committed to that departed devotee.
Srila Prabhupada also established reciting the Vaisnava pranama mantra after managala arati every day in all temples. He explicitly responded to your above-stated question that this was one way to seek forgiveness for the offenses one may have committed unknowingly.
väïchä-kalpatarubhyaç ca
kåpä-sindhubhya eva ca
patitänäà pävanebhyo
vaiñëavebhyo namo namaù
“I offer my respectful obeisances unto all the Vaiñëava devotees of the Lord. They can fulfill the desires of everyone, just like desire trees, and they are full of compassion for the fallen souls.”