Changing Equallogic blade Array PS-M4110 IP Addresses

PS-M4110 has only two eth; eth0 and eth1. Once I enabled dedicated network management, eth1 marked as mgmt-only and the other one is for SAN as usual. eth0 is DCB enabled and assigned vLAN. the box has one group only with one member.

I faced a difficulty when I want to change the SAN IP. there is no additional eth can be used as a temporary to put the new IP on it in order to be able to change group IP. therefore, I planned to revert back dedicated network management and use it for iSCSI similar what seen in default configuration.

at this point, I am able to remove dedicated network management from the group. but when I work with the member I failed disabling mgmt-only with the following error messages:

DellPS4110(member_EQLSLOT15-member eth_1)> show
_______________________________ Eth Information _______________________________
Name: eth1                             Status: up                      
Changed: Sat Apr 14 04:11:38 2018      Type: ethernet-csmacd           
DesiredStatus: up                      Mtu: 1500                       
Speed: 100 Mbps                        HardwareAddress: C8:xx:xx:xx:xx:xx
IPAddress:                             NetMask:                        
IPv6Address:                           Description:                    
SupportsManagement: only               ManagementStatus: enabled       
DCB: off                                                               
_______________________________________________________________________________
DellPS4110(member_EQLSLOT15-member eth_1)> down
Disabling the dedicated management interface on a member will cause one of the i
SCSI interfaces to carry management traffic.

Disable the interface only for a short time (for example to move cables) and onl
y if you have access to a serial port on the member.

Do you want to disable the management interface? (y/n) [n]y

% Error - Cannot disable this interface. Interface must remain enabled.
DellPS4110(member_EQLSLOT15-member eth_1)> mgmt-only disable
% Error - The interface is dedicated to management operations only and is not al
lowed to be configured for iSCSI access.

Does anybody have an idea or workaround this ? or give the correct procedures. None-blade-array is easier  to change as there are more than one eth for SAN.