You can melt anything you bought with real cash or got as gift in your web hangar and get the credit value of it in credits.
Then buy new packs or ships and you can buy the melted pack back with new cash or using a buyback token the melted pack if you so chose to later,
There is no difference if it's a warbond or not once you bought it it's yours in web hangar or in buyback, but you only got access to the ship/gear in game that is in your web hangar.
BUT! Warbond can only be bought with new cash in store, but can be bought back with buyback token and credits and as Sunder say you can not split packs they are as one.
Exception some early packs and and rare special packs you can not buyback, but they warn you that it can not be undone or bought back if you melt them. (but you still get the credit value for them.)
CHEERS!!