The PartitionDN element contains the DN of the root of the naming context (NC), which represents the NC that contains the principal specified in ChangePasswordRequest/AccountDN.

 <xs:element minOccurs="0" name="PartitionDN" nillable="true" type="xs:string" />

The PartitionDN element refers to the directory instance root directory object of the NC ([MS-ADTS] section that contains the directory object referenced by ChangePasswordRequest/AccountDN.