If you have build a new Domain controller for the exchange environment and you wanted your exchange servers to user this domain controllers then below command can help is setting the same. You can also statically exclude not to use specific domain controller with the command

$Exchserver = “ExchagneServerName”

set-exchangeserver $exchserver -StaticDomainControllers:New_DC1,New_DC2

set-exchangeserver $exchserver -StaticGlobalCatalogs:New_Gc1,New_GC2

set-exchangeserver $exchserver -StaticExcludedDomainControllers:Old_Dc1,OldDC2

This can also be clubbed in a single line

Get-ExchagneServer $ExchServer -status | FL

Will get the details which are statically applied in above line. Some result may come in blank but using -status will get the results to display