The AUTO_INCREMENT clause can change the initial value of the increment value that is currently defined. However, there should be only one AUTO_INCREMENT column defined.
ALTER TABLE table_name AUTO_INCREMENT = initial_value;
CREATE TABLE t (i int AUTO_INCREMENT);
ALTER TABLE t AUTO_INCREMENT = 5;
-- when 2 AUTO_INCREMENT constraints are defined on one table, it returns error.
CREATE TABLE t (i int AUTO_INCREMENT, j int AUTO_INCREMENT);
ALTER TABLE t AUTO_INCREMENT = 5;
ERROR: To avoid ambiguity, the AUTO_INCREMENT table option requires the table to have exactly one AUTO_INCREMENT column and no seed/increment specification.
You must be careful not to violate constraints (such as a PRIMARY KEY or UNIQUE) when you alter the initial value of AUTO_INCREMENT.