If someone improperly convinces another person to change his or her will, then the people who are harmed as a result need legal remedies to undo that harm. For example, if an unscrupulous attorney convinces an elderly parent to change his or her estate plan to exclude the children and benefit the attorney, then the children need legal remedies.
The most common remedy is to go to probate court and make a claim of undue influence after the parent has passed away.
If the court finds that there was undue influence, then the changed estate plan can be disregarded in favor of an older one. Another possible remedy is filing a suit for tortious interference with inheritance rights.
Texas Supreme Court recently considered this issue as the Wills, Trusts & Estates Prof Blog discussed in "Unanswered Questions in Texas."
Instead of suing the estate in probate court, as is done in an undue influence case, in a tortious interference with inheritance rights, the person accused of improper influence is sued directly for the damages that he or she has caused.
Depending on the jurisdiction and the facts of the case, this is a cause of action that can be used instead of or in conjunction with an undue influence claim.
The Supreme Court in Texas was asked to determine whether the cause of action exists in Texas. Lower Texas' courts are split on the issue.
Instead of doing that, however, the court declined to do so. It determined that where undue influence exists, a constructive trust is a sufficient remedy for damages.
Reference: Wills, Trusts & Estates Prof Blog (June 2, 2017) "Unanswered Questions in Texas."