law: The Indian Succession Act, 1925
  Chapter V.- Of the Attestation, Revocation, Alteration and Revival of Wills
  67. Effect of gift to attesting witness.-
  A will shall not be deemed to be insufficiently attested by reason of any benefit thereby given either by way of bequest or by way of appointment to any person attesting it, or to his or her wife or husband; but the bequest or appointment shall be void so far asconcerns the person so attesting, or the wife or husband of such person, or any person claiming under either of them.
  Explanation.-A legatee under a will does not lose his legacy by attesting a codicil which confirms the will.
  68. Witness not disqualified by interest or by being executor.-
  No person, by reason of interest in, or of his being an executor of, a will, shall be disqualified as a witness to prove the execution of the will or to prove the validity or invalidity thereof.
  69. Revocation of will by testator's marriage.-
  Every will shall be revoked by the marriage of the maker, except a will made in exercise of a power of appointment, when the property over which the power of appointment is exercised would not, in default of such appointment, pass to his or her executor or administrator, or to the person entitled in case of intestacy.
  Explanation.-Where a man is invested with power to determine the disposition of property of which he is not the owner, he is said to have power to appoint such property.
  70. Revocation of unprivileged will or codicil.-
  No unprivileged will or codicil, nor any part thereof, shall be trevoked otherwise than by marriage, or by another will or codicil, or by some writing declaring an intention to revoke the same and executed in the manner in which an unprivileged will is herein before required to be executed, or by the burning, tearing, or otherwise destroying the same by the testator or by some person in his presence and by his direction with the intention of revoking the same.
  Illustrations
  (i) A has made an unprivileged will. Afterwards, A makes another unprivileged will which purports to revoke the first. This is a revocation.
  (ii) A has made an unprivileged will. Afterwards, A, being entitled to make a privileged will, makes a privileged will, which purports to revoke his unprivileged will. This is a revocation.
  71. Effect of obliteration, interlineation or alteration in unprivileged will.-
  No obliteration, interlineation or other alteration made in any unprivileged will after the execution thereof shall have any effect, except so far as the words or meaning of the will have been thereby rendered illegible or undiscernible, unless such alteration has been executed in like manner as hereinbefore is required for the execution of the will:
  Provided that the will, as so altered, shall be deemed to be duly executed if the signature of the testator and the subscription of the witnesses is made in the margin or on some other part of the will opposite or near to such alteration, or at the foot or end of or opposite to a memorandum referring to such alteration, and written at the end or some other part of the will.
  72. Revocation of privileged will or codicil.-
  A privileged will or codicil, may be revoked by the testator by an unprivileged will .or codicil, or by any act expressing an intention to revoke it and accompanied by such formalities as would be sufficient to give validity to a privileged will, or by the burning, tearing or otherwise destroying the same by the testator, or by some person in his presence and by his direction, with the intention of revoking the same.
  Explanation.-In order to the revocation of a privileged will or codicil by an act accompanied by such formalities as would be sufficient to give validity to a privileged will, it is not necessary that the testator should at the time of doing that act be in a situation which entitles him to make a privileged will
  73. Revival of unprivileged will.-
  (1) No unprivileged will or codicil, nor any part thereof, which has been revoked in any manner, shall be revived otherwise than by the re-execution thereof, or by a codicil executed in manner hereinbefore required, and showing an intention to revive the same.
  (2) When any will or codicil, which has been partly revoked and afterwards wholly revoked, is revived, such revival shall not extend to so much thereof as has been revoked before the revocation of the whole thereof, unless an intention to the contrary is shown by the will or codicil.