anybody know how to change the blade of a milwakee skill saw with 6.5 inch blade?

Answer 1

I know!! It's the same way you would do it with any other kind. Block the blade with a piece of wood and loosen the bolt.

Answer 2

Check the direction of the hold-down bolt on the arbor.
It might use left-hand threads.

Worm drive saws from Skil have left-hand threaded bolts. There are directional arrows on the head of the bolt showing which way to remove.

Not sure if Milwaukee marks its bolts.