Support was able to fix the problem. here is what they did: (note, you will need to change XXXXXXX.onlinehome-server.com to you domain and root@XXXXXX to root@your-user-name.).
"Thank you for contacting Odin Technical Support.
It was nice talking to you over the phone. I am glad to inform you that the issue has been resolved by correcting the database inconsistency in the psa database. I have added some missing table entries to resolve this case. Please check the following snippet for more details.
+++===
[root@XXXXXX ~]# mysql -uadmin -p`cat /etc/psa/.psa.shadow` psa
mysql> insert into ServiceInstanceProperties values (1, "root", "/var/www/vhosts/XXXXXXX.onlinehome-server.com");
Query OK, 1 row affected (0.06 sec)
mysql> select * from ServiceInstanceProperties;
+-------------------+------+-------------------------------------------------+
| serviceInstanceId | name | value |
+-------------------+------+-------------------------------------------------+
| 1 | root | /var/www/vhosts/XXXXXX.onlinehome-server.com |
+-------------------+------+-------------------------------------------------+
1 row in set (0.00 sec)
mysql> select * from ServiceInstances;
Empty set (0.00 sec)
mysql> insert into ServiceInstances values (1,2,1,'',1,1);
Query OK, 1 row affected (0.05 sec)
mysql> insert into ServiceInstances values (2,1,1,'',1,1);
Query OK, 1 row affected (0.07 sec)
++====
Now I am able to change the hosting type without any problems. Please verify the same from your end. If you need any further help, feel free to get back to us. I will be glad to assist you further."