Transferring a FSMO (Flexible Single Master Operations) Role using the NtdsUtil.exe is pretty easy.

Start a Command Line (cmd.exe)
C:\>ntdsutil.exe
Switch to Roles context
ntdsutil: Roles
Switch to Connections context
fsmo maintenance:Connections
Optionally you can specify the credentials used to connect the the server
The format is server connections:set creds MYDOMAIN MYUSERNAME MYPASSWORD
Connect to the specific server
connect to server SERVERNAME
Quit this context
server connections: quit
Now you can transfer the FSMO Roles using the transfer command.
Transfer Schema Master

possible roles to transfer are:
Transfer domain naming master
Transfer infrastructure master
Transfer PDC
Transfer RID master
Transfer schema master

To get a list of all the FSMO Roles for a specific server, read here – List FSMO Roles of a Domain Controller