Is SQL Server able to use internal parallelism for an update statement?

Question

I am struggling to find the best way to migrate some varchar columns to nvarchar. One of the options I am using is to add new nvarchar column, then update the values from the original column, drop the original column and rename the new one to the old name.

I know it will generate a lot of UNDO and REDO data. Still, I have other limitations (mostly by SQL Server not supporting parallel DDLs and multi-column ALTER TABLE operations), so let's focus on how to run the update statement faster.

My Oracle experience is telling me to use internal parallelism, but is it available in SQL Server?

I am not able to run this statement in parallel, although I especially created the table to be a heap table (no clustered index).

update t 
set new_col_1 = col_1,   
    new_col_2 = col_2, 
    ..., 
    new_col_N = col_N ;

Thanks in advance!!

I read the documentation but have not find an exact proof that parallel update plans are possible.