Delete a registrar
Removes a registrar from your list.
Check what is assigned to it first
Open Domain names and sort or search by registrar to see what points at this one. Every domain assigned to a registrar you delete loses its answer to "where did this come from", and reconstructing that later means going back through your registrar accounts.
If domains are still assigned to it, reassign them first by editing each domain.
What it does not do
Deleting a registrar record changes nothing at the registrar. Your account there is untouched, your domains are still registered, and renewals still happen. This list is Flexi Domains' record of who you buy from, not a connection to them.
When to use it
Delete a registrar you no longer buy from and have no domains with, or one added twice by mistake. Duplicate entries are the common case: reassign the domains to the entry you are keeping, then delete the other.