in general procedure for 7mode
1. upgrade the olde node to the same version as new one
2. shutdown old one, turn off all the shelves
3. connect all shelves to new one
4. turn on shelves firstly, then new head
5. go to maintennance mode to assign the disks to new node
6. boot it up normally
7. check licenses (should be fine, up to the version of ontap)
hopefully helps
Jeff