1 list with many records copy to new list with no duplicates

How do i iterate 1 list and populate a new list with only the Unique values in the first list ?

example list 1 contains (1,2,3,4,4,5,5,6,7,8,8,8,8)

I need a new list to contain (1,2,3,4,5,6,7,8)
Pretty simple.  Create an action with an input variable for the starting list (must be in sequence), an output variable for the new list and a local vairable with a default value of zero..  In this action use For Each to loop through the input list.  If the value you are testing is not equal to the local variable, move the data to the new list.  Set the local variable to the value just read and then go back to the loop.