Can a release form signed by client of a lawyer be reversed? -

I a lawyer has misguided the client , and was paid in full , and as it turned out did not do his job . Later the not so intelligent client signed a release form without reading it , that basically relieves the lawyer from being held liable for anything . Can this mistake on the behalf of the client somehow be reversed , or disputed ?

Almost certainly not. This is a document that protects the interests of a person. The person who signed it may now change his mind, but would need to persuade the person receiving the document to give up this valuable thing without compensation. I do not see that as reasonable. Of course, you could consult your attorney to find out whether or how you could work around this problem.