if any major sin took place then what are the ways to get rid of it

Please refer to the following link for a detailed answer regarding sins and repentance.

Islam Question and Answer - Means of expiating sin


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I think if you have done a major sin, then if you realize your mistake, not let it happen again, apologize from anyone who was offended, do good deeds and ask Allah for forgiveness then it is very likely that he will forgive u