Melvin and Betty Franklin (defendants) signed an installment contract to buy a car from Essco Motors (Essco) (plaintiff). The Franklins signed a promissory note for the $1,656 that remained due after their down payment. The Franklins’ monthly payments were due on the 15th of each month. The Franklins paid their monthly payments on time in February and March 1966. The Franklins testified that in April, they received verbal permission from Essco to change their payment due date to the 27th of each month. The Franklins then made each payment from April to October 1966 by the 27th of each month. Essco accepted each of these payments. In November 1966, Essco could not reach the Franklins to track down their monthly payment. As a result, Essco had the car repossessed. Essco then sued on the promissory note. The Franklins filed a counterclaim, asserting that Essco’s repossession of the car was fraudulent and constituted conversion. The trial court ruled in favor of the Franklins, granting their counterclaim. Essco appealed.