Undue Influence in Texas is usually brought up in the context of contesting a will. However, any document that was signed because the person signing the document was being unduly influenced can be set aside. Things like wills, deeds, survivorship accounts at banks,etc.
The burden of proof is upon the person claiming undue influence. To set aside an instrument based on undue influence, the party claiming undue influence must prove (1) the existence and exertion of an influence; (2) the effective operation of such influence so as to subvert or overpower the mind of the property owner at the time the instrument was executed; and (3) the execution of an instrument that the property owner would not have executed but for such influence. If there is a formal or informal fiduciary relationship between the person signing and the beneficiary of the document, the burden may shift to the beneficiary. 09-17-00203.