Hi Paul,
I would suggest to you do this activity under maintenance window.
We have to unconfigure slot 1 and this will remove the configuration from the node that to be
replaced from stack.
All configuration parameters (except for the related node's NVRAM-based configurations such as
stacking parameters, image to be used, and failsafe account) for the slot will be erased.
Follow the steps to add a new node which I have shared on the article and load the modified configuration to the replacement switch.
Thanks,
Suresh.B