You can explicitly create an iterable with the iter()
builtin, then call `next(iterable) to consume one item. Final result is something like this:
line_iter = iter(list_of_lines[:])
# consume first item from iterable
next(line_iter)
for index, item in enumerate(line_iter, start=1):
list_of_lines[index][1:3] = [''.join(item[1:3])]
Note the slice on the first line, in general it's a bad idea to mutate the thing you're iterating over, so the slice just clones the list before constructing the iterator, so the original list_of_lines can be safely mutated.