defender 6.2 new build impact on existing

Hi,  I am looking to install Defender 6.2 on a new W2019 server as part of an upgrade.

This is to replace an existing W2008 Defender 5.8.1 server. 

During the 6.2 install it asks to update Active Directory. 

Can I install and build the new server without affecting the operation of the existing server? 

Also can i use the same AD service account?