I'm assuming by the question that these are not held in a tax-advantaged account
One other thing to throw in: even if you decide to not sell quite yet for those funds (such as if there are significant short-term gains, or if there's a back load that will expire in a year or so), re-direct dividends out of the account - such as to your bank account. Use those to buy an equivalent amount of your preferred Vanguard funds.