Oracle Apex - Delete member from collection

Is it possible delete from apex collection where C003 = 31

The DELETE_MEMBERS procedure is what are you looking for. To find out more about it please check the official Oracle documentation.

You can do something like:

APEX_COLLECTION.DELETE_MEMBERS 
(
    p_collection_name => 'collection_name',
    p_attr_number     => 3,
    p_attr_value      => '31'
);

Or use the sequence ID.

DECLARE

    CURSOR c_temp IS
    SELECT
        seq_id
    FROM APEX_COLLECTIONS
    WHERE collection_name = 'collection_name'
        AND c003 = '31';

BEGIN
    FOR r_temp IN c_temp LOOP
        apex_collection.delete_member
        (
            p_collection_name => 'collection_name',
            p_seq => r_temp.seq_id
        );
    END LOOP;
END;