Q. If you have wronged someone and the person is not around for you to ask their forgiveness, what can you do (what is the proper way of making tauba)?
A. If the person is alive then you should try your best to get in contact with the person via phone, email or letter and ask for forgiveness.
If you cannot get in contact, then you should make dua to Allah and beg Allah to forgive you for the wrong you have done.
If the person has died, then you will have to make dua to Allah, begging for his forgiveness.
In both cases of making dua, you should also beg Allah for the person to forgive you so that he will not take you to task on the day of judgement.
And Allah knows best.
Mufti Waseem Khan