It is possible to relive some phases of this or some previous lifespan in meditation. It may even occur in flashes when not in meditation, when wide awake. Several yoga masters of repute reported about knowing of their past lives. There is the famous statement of Krishna, the person who identified himself as the Supreme Lord (parameshvaram/bhagavan):
बहूनि मे व्यतीतानि
जन्मानि तव चार्जुन ।
तान्यहं वेद सर्वाणि
न त्वं वेत्थ परंतप ॥४.५॥
bahūni me vyatītāni
janmāni tava cārjuna
tānyahaṁ veda sarvāṇi
na tvaṁ vettha paraṁtapa (4.5)
śrī bhagavān — the Blessed Lord; uvāca — said; bahūni — many; me — of Me; vyatītāni — transpired; janmāni — births; tava — your; cārjuna = ca — and + arjuna — Arjuna; tānyahaṁ = tāny (tāni) — them + aham — I; veda — I recall; sarvāṇi — all; na — not; tvaṁ — you; vettha — you remember; paraṁtapa — O scorcher of the enemies
The Blessed Lord said: Many of My births transpired, and yours, Arjuna. I recall them all. You do not remember, O scorcher of the enemies. (4.5)
भूतानामीश्वरोऽपि सन् ।
ajo = ajaḥ — birthless; 'pi = api — even though; sann = san — being; avyayātmā = avyaya — imperishable + ātmā — person; bhūtānām — of the creatures; īśvaro = īśvaraḥ — Lord; 'pi = api — even; san — being; prakṛtiṁ — material energies; svām — my own; adhiṣṭhāya — controlling; saṁbhavāmyātmamāyayā = sambhavāmy (saṁbhavāmi) — I become visible + ātma — self + māyayā — by supernatural power
Even though I am birthless and My person is imperishable, and even though I am the Lord of the creatures, by controlling My material energies, I become visible by My supernatural power. (4.6)
Depending on his existential category and psychic clarity, a yogi may remember portions of past lives and parts of infancy but the memory may not be coherent as in recent recall of physical and dream state events.
During a morning meditation just after completing breath infusion practice for one hour, I has an experience at the third eye chakra of the mother of my current body. This lady is deceased. She was in her subtle body which assumed the appearance of what her previous physical form was in the past life when I was a four month old infant in her arms. She held me to her right breast. Her mood was one of expectancy as would be of a young woman who waited for her husband to return home.
As it played out in their lives her husband (the father of my body) did not complete his parental or spousal responsibilities in the ideal way.
The value of this experience for me is that as an infant of a woman, one does not see anything besides that woman, the mother, while she, the mother is always expectant for time and circumstance to be favorable to her, even though it may not be.
In the experience I was keen to observe the perspective of myself as that infant of the lady. In that mental posture, there was no idea about yoga practice. It seems that my existence was only turned to being something which was to be nourished by this woman.
Infancy is a flat down cancellation of higher aspirations with a focus on dependency in relation to survival of the infant body. One exists then as a surviving unit, a cell, so to speak.
Recollection of previous birth gives the yogi the advantage of understanding how he was transported into the new birth circumstance, on the basis of his and the prior acts of other persons whom he meets in the present life and in whose association he is tailored to relate and act in a certain way.
It gives him a perspective on how history unfolds so that he can understand the ways of destiny rather than be like an ordinary person who can only rationalize everything in terms of what happened in the present birth only and also what happened collectively according to the report from books about history.
An example of not understanding this was King Bharat, son of Rishabha, who by emotional relationship with deer took a deer body and then resumed human embryo but in the resumption remembered what happened consciously and took steps to act in a way which prevented his assumption of a lower species.
Just to be good, to follow moral principles, is not enough to prevent lower birth or haphazard birth circumstance. Bharat was a good guy and his act of sheltering and being affectionate to deer was good and praiseworthy but its results were degrading nevertheless. Hence if one can remember the past live(s), and if one applies the insight derived one will act in a way which will prevent one from taking lower births which may cause one to completely lose the foot hold on self-realization.