Yes since using that route only switch is accessible mostly if you are using that IP to access.
So basically if you remotely access switch using same you might have to use Console option to do such changes.
you need to do below steps.
1. Change mgmt ...
Are you using any tools to manage the Fabric, If not I would recommend using Cisco NDFC tool which is very handy and easy to manage Cisco Nexus fabric operations and additions.
Also instead of adding Spine in same fabric u can try to use Multisite Fa...
