Guild Wars 2

How do i change the stats on them

If I do will they change the appearance of the incinerator

Can i apply different sigils on them??? and still keep the skin?

You double click on the weapon to select the stat if you have the weapon equipped.
If the weapon is not equipped you right click on it and select the ‘Select stat’ option.
You are free to do whatever you want with the sigil.

None of those things have any effect on the skin.

Double click the equipped weapon icon to change stats. This opens a window with a drop down box where you pick the name of the stat combo you want (Assassins, Berserker, Soldiers, etc) You can do this anytime you are out of combat.

Doing this does not change the appearance or effects of your Legendary.

Sigils do not change the appearance or effects of your Legendary, you can change them as often as you wish.

Grats on Incinerator!