Method for operating an exhaust-gas treatment device having a store in which a quantity of a reducing agent can be temporarily stored, an SCR catalytic converter, a hydrolysis catalytic converter, at least one heater and at least one supply device for a reducing agent, which method comprises at least the following steps: a) checking whether reducing agent should be supplied; b.1) heating by means of the heater until a first threshold temperature, assigned to the hydrolysis catalytic converter, is reached, if a determined first temperature lies below the first threshold temperature and if, according to step a), reducing agent should be supplied, wherein the first threshold temperature is selected such that at least a hydrolysis in the hydrolysis catalytic converter can take place if the first temperature lies above the first threshold temperature; b.2) heating by means of the heater until a second threshold temperature, assigned to the SCR catalytic converter, is reached, if a determined second temperature lies below the second threshold temperature and if, according to step a), no reducing agent should be supplied, wherein the second threshold temperature is selected such that a selective catalytic reduction of nitrogen oxide compounds in the SCR catalytic converter can take place if the second temperature lies above the second threshold temperature and wherein the second threshold temperature lies below the first threshold temperature; and c) supplying reducing agent if, according to step a), reducing agent should be supplied. a) checking whether reducing agent should be supplied; b.1) heating by means of the heater until a first threshold temperature, assigned to the hydrolysis catalytic converter, is reached, if a determined first temperature lies below the first threshold temperature and if, according to step a), reducing agent should be supplied, wherein the first threshold temperature is selected such that at least a hydrolysis in the hydrolysis catalytic converter can take place if the first temperature lies above the first threshold temperature; b.2) heating by means of the heater until a second threshold temperature, assigned to the SCR catalytic converter, is reached, if a determined second temperature lies below the second threshold temperature and if, according to step a), no reducing agent should be supplied, wherein the second threshold temperature is selected such that a selective catalytic reduction of nitrogen oxide compounds in the SCR catalytic converter can take place if the second temperature lies above the second threshold temperature and wherein the second threshold temperature lies below the first threshold temperature; and b.1) heating by means of the heater until a first threshold temperature, assigned to the hydrolysis catalytic converter, is reached, if a determined first temperature lies below the first threshold temperature and if, according to step a), reducing agent should be supplied, wherein the first threshold temperature is selected such that at least a hydrolysis in the hydrolysis catalytic converter can take place if the first temperature lies above the first threshold temperature; b.2) heating by means of the heater until a second threshold temperature, assigned to the SCR catalytic converter, is reached, if a determined second temperature lies below the second threshold temperature and if, according to step a), no reducing agent should be supplied, wherein the second threshold temperature is selected such that a selective catalytic reduction of nitrogen oxide compounds in the SCR catalytic converter can take place if the second temperature lies above the second threshold temperature and wherein the second threshold temperature lies below the first threshold temperature; and c) supplying reducing agent if, according to step a), reducing agent should be supplied.