[Path] enlarge magic weapon

[Icarion]

Here's the thing:
Our group (lv4 wizard/ninja/fighter) found a magic longsword (medium) which our fighter HAS to use.
The problem is that our fighters build focuses on two handed weapons (falchion weapon focus ) and critical feat chain ( feats are: power attack , weapon focus:falchion , cleave , step up , furious focus &dazzling display )
The question:
Is it any way that the fighter can enlarge the magical longsword so it passes as a greatsword ? (then changing the focus to greatsword)

If its not , do you have an alternative to improve the build ? (lawful evil human fighter)

Thnx for the feedback guys !!

[jaydubs]

You could enchant the longsword with the transformative property (10,000 gold, but doesn't add to future weapon bonus costs). That lets the weapon turn into another similar sized and handed weapon. So a medium longsword can be turned into a medium scimitar or cutlass.

You can two hand either of those. And while 1d8 isn't quite as good as 2d4, you're really only losing 0.5 damage on average. They both have that 18-20 crit range you're after.

[Icarion]

Thnx ! We just realized that it is in fact an intelligent item. We can enchant those since they are magical weapons that can be crafted , can we ?

Sorry for the english.