Update sql statement for DELETING DUPS in 2 fields

sql server 2008
What I need:
To delete duplicates based on 2 fields.

 


1 table:
In my Table...
field 1  =  "Material_no"  is a PK field(Yes dups ok).
field2 =   "alt_acc_material_no" (pk field no dups)
Right now I'm using cte to delete dups from a table with 1 primary field...


code for one primary field:
with CTE as (
      select *, row_number() over (partition by material_no order by material_no) rn
      from crs_staging
)
delete from CTE where rn > 1

1A123       4RRT5     < OK
1A123       55T56     <  OK
1SS23       1WW25  
5TT56        666T6      
5TT56        666T6            <----- DELETE



Thanks
fordraiders