how to change name of simulink blocks through matlab code

exl = actxserver('excel.application');

exlWkbk = exl.workbooks.Add;

new1= readtable('names.xlsx');

list_of_block_in_subsystem = find_system('Auto_Script','type', 'block');

for i = 1:length(list_of_block_in_subsystem)

old_name = get_param(list_of_block_in_subsystem{i},'Name');

new_name = new1.aa{i};

set_param(list_of_block_in_subsystem{i}, 'Name', new_name);

end

%code is not running completely only half of the names changes and also code is executing only ones.