Lower Spell Slots into Higher Spell Slots

[metabolicjosh]

What is the feat that lets you make several lower spell slots into a higher spell slot, and vice versa?

[Flickerdart]

Versatile Spellcaster allows you to dump two spells to cast one spell of one level higher. I don't think there's a feat that does the opposite, but take a look at Rary's Mnemonic Enhancer and Mordenkainen's Lucubration, both of which allow you to recall X levels of lower level spells when you cast them.

[Siosilvar]

Versatile Spellcaster, RotD page 101.

There is no "vice versa", but you can use a lower-level spell in a higher slot.
A spellcaster always has the option to fill a higher-level spell slot with a lower-level spell.

[metabolicjosh]

Thank You ill look for the feats Errata on DNDTOOLS

[eggs]

and vice versa?
Arcane Manipulation? (http://www.wizards.com/default.asp?x=dnd/ex/20050202a)

This is also a default assumption to the spells in Arcana Unearthed, so that could count as a 3rd party source (that said, AU makes problems if it's not treated as its own system).

[metabolicjosh]

Sorry but i'm a sorcerer because a good sorcerer is always better than a good wizard. At least when your dm plays it where you must buy all you spells by finding a wizard to teach it. But i gets its for free.

[Reluctance]

Complete Mage has Arcane Fusion and Greater Arcane Fusion. You can use a higher level slot to cast two lower level spells, with the major advantage being that they cast simultaneously.

If you want your spell slots to be perfectly interchangeable, though, psion is really where it's at.