When you try to delete a license from sddc manager manager it fails and throws a error message that it is in use, like below
This would happen if you need to update, clean your licensing on one or more products on a VCF deployed environment. You can update SDDC manager with a new license but you will still need to apply the license directly on the product (such as vCenter)
This is the workaround to update the licenses on sddc manager
ssh to sddc manager
login in as vcf
su
cd /
psql –host=localhost -U postgres
\c operationsmanager
\x
select * from licensemanager.licensekey;
delete from licensemanager.licensekey where key=’55555-55555-55555-55555-55555′;
\q
add new license through sddc manager
Go to vcenter and add the key there too, as sddc manager doesn’t do this