Remove rows from child tables using nhibernate nhsession -

i have mapping of feedbacksessions (parent table) , resultrows table (child table). need delete rows child table using nhsession.

how delete rows child table , update parent table ?

        manytoone(x => x.resultrow, m =>         {             m.column("resultrowid");             m.notnullable(false);             m.foreignkey("fk_feedbacksessions_resultrows");             m.cascade(cascade.all);         });