Find duplicates based when another column has two different values

Not sure if you need a DAX table or a measure to use in a table visual (or want this done in your query), but here is a DAX table expression that shows one way to do it.  Just replace "Accounts" with your actual table name.

YesAndNo =
VAR vSummary =
    SUMMARIZE ( Accounts, Accounts[Account], Accounts[New] )
VAR vResult =
    FILTER (
        DISTINCT ( Accounts[Account] ),
        VAR vThisAccount = Accounts[Account]
        RETURN
            SUMX ( FILTER ( vSummary, Accounts[Account] = vThisAccount ), 1 ) = 2
    )
RETURN
    vResult

Pat