Manu Smriti 11.227. By confession, by repentance, by austerity, and by
reciting (the Veda) a sinner is freed from guilt, and in case no other
course is possible, by liberality
11.228. In proportion as a man who has done wrong, himself confesses it, even so far he is freed from guilt, as a snake from its slough.
11.229. In proportion as his heart loathes his evil deed, even so far is his body freed from that guilt.
Although repentance is a valid mode for getting rid of sins there are no definite guidelines on how to repent. The feeling should be sincere and coming from one's heart with the genuine feeling of being sorry for whatever bad deeds one had done in the past. The more sad one feels for their bad deeds more sins are cleared off thereby.
One more reference:
Surely, a fat, unruly, fierce, and bellowing bull, attacking
creatures and saying what he pleases, does not reach the gods. It is
the tiny ones with emaciated bodies who reach there.
32 At various times in his youth a man may have foolishly done all
sorts of good or evil deeds. If, however, in his later years he leads
a virtuous life, only that will follow him, not the acts of his youth.
33 Leading an austere and vigilant life, let him always grieve in his heart when he recalls his misdeeds. He will thus be freed from
those sins.
Dharmasutras of Baudhayana 1.11.7.31-33
In case , the person forgives us , do we get rid of the sin ?
27 If a man extinguishes his sacred fires, he should perform an
arduous penance for twelve days and have the rite of establishing the
sacred fires carried out over again.
28 If someone falsely accuses an elder of his, he should bathe with
his clothes on and seek forgiveness from that elder. ‘He becomes
pure’, it is stated, ‘by his forgiveness.’
Dharmasutras of Vashishta 21.27,28
So, seemingly it is certainly possible to become sin free if he has been forgiven but it might also depend on the particular sins one has committed. So, IMO answering generally might not be possible.