There are two ways to revoke a will: by subsequent testamentary instrument or by physical act. The Texas probate code, section 63, specifies these two exclusive ways that a will can be revoked. Section 63 says:
"No will in writing, and no clause thereof or devise therein, shall be revoked, except by a subsequent will, codicil, or declaration in writing, executed with like formalities, or by the testator destroying or canceling the same, or causing it to be done in his presence."
Subsequent Testamentary Instrument: To revoke a will by subsequent testamentary instrument, the testator must have testamentary capacity. If he does not have testamentary capacity, the attempted revocation by a subsequent will is ineffective. If the subsequent will is not admitted to probate for some reason, i. e., the will was denied probate because it was the result of undue influence for example, it is void in toto, every provision of it, and it cannot serve to revoke a former will. 761 S.W.2d 448. The testamentary instrument used to revoke a will, does not have to be a will itself. As long as it is in writing and executed with the same formalities of a will, a paper saying as little as "I revoke my will" is sufficient to revoke a prior will.
Since revocation by implication is not favored, if the testator has a will and then executes a subsequent will that does not specifically say he is revoking the first will, the two wills will be read together as much as possible and the second testamentary instrument will be treated as a codicil to the first will.
Revival of revoked wills: when a testator executes a will and then subsequently executes a second will revoking the first will and then later on decides that he wants the first will to be his will, merely destroying the second will will not revive the first will. In order to revive the first will, the testator must re-executed with the formalities required by law.
Physical Act: The physical act of revocation by destroying the will must be the destruction of the will itself. The intent to destroy without actually destroying the will is insufficient. In one case, the testator tore up an envelope which he thought contained the will. It did not contain the will and the court held that his intention to destroy it without actually destroying it did not revoke the will.
The physical destruction must be of the entire will. A testator cannot destroy a sentence or a paragraph in a will such as scratching through them. The strikeout will be ignored by the courts.
There are some statutes that revoke portions of the will without any action by the testator. For instance, if a testator makes a will and then later divorces his wife who was named in the will, all provisions in his will in favor of the wife are void. Likewise, if the testator executes a will and then later as a child who is not mentioned in the will or otherwise provided for, the law will allow the child to take a portion of the testator's estate.