Although Dirk's answer is correct, the RevDump tool only works on Windows Server 2003, since newer versions of Windows store reversibly encrypted passwords in a different way . So I created a new tool that supports Windows Server 2008+.
The simplest use case:
Get-ADReplAccount -SamAccountName April -Domain Adatum -Server LON-DC1
():
DistinguishedName: CN=April Reagan,OU=IT,DC=Adatum,DC=com
Sid: S-1-5-21-3180365339-800773672-3767752645-1375
SamAccountName: April
SamAccountType: User
NTHash: 92937945b518814341de3f726500d4ff
SupplementalCredentials:
ClearText: Pa$$w0rd