Wrong email id on letter of recommendation
Never ever manipulate a letter written by a third person. 

Explain the discrepancy, yes. You have to hope they accept the explanation. 

However, if you manipulate, you are committing fraud, breach of trust, and you will be blacklisted where this is possible. You may also lose your recommender for the future if he gets to hear about that (e.g. if they manage to check with him). In some countries (such as Germany), manipulating official documents is explicitly a crime and can be punished with years in prison.