Move My Cloud EX2 Ultra from one wifi-network to another

My Cloud EX2 Ultra is currently connected using my 5G network. For various reasons I need to move it over to my N-network (the non-5G) WIFI SSID from same router.
Can someone guide me step by step how to do it (obviously without losing the data).

Not sure what you’re asking. The EX2 doesn’t connect via wifi, it’s connected to your router directly. Are you using a wifi dongle bridge?

I probably was not clear, Sorry.
Currently my EX2 is accessed (from my desktop, mobile phone, TV) by using a specific IP address that is located on a network which is controlled by a 5G Router. I have another network controlled by a non-5G router (N). Each network has its own SSID, so they run in parallel and not collide.
To access the EX2 currently I must connect using the SSID of the 5G-Router. I would like to access my EX2 using the N-SSID (the non-5G-Router).
To do that I believe I need to configure the EX2 so its IP Address will be obtained from the non-5G network, and all my devices can access the EX2 by connecting into the N-Router / SSID.
I do not know how make that

Still don’t understand what SSID has to do with it. You are currently connected via ethernet to one router and you now wish to connect via ethernet to the other router?

in order to access my EX2 I need to connect my mobile phone or my desktop to a specific Wi-Fi network (that is where the SSID come to play. The Wi-Fi network i must use for that is my 5G network.
I have to use that network since the IP address ( that the EX2 is using is part of that 5G router.
I want to use a different Wi-Fi network - my non-5G - the IP address range that the non 5G router provides is
I need the EX2 to use rather than
How can I control the IP Address that the EX2 has.
Normally the EX2 will connect to a DHCP and this will provide it an address. But I want it to access a specific DHCP or alternatively if I can manually assign the EX2 an IP address (say I can assign on my non %G router a static IP for the EX2 on it.

Ah, OK, I get you. So you basically have 2 home networks and you want to move the NAS from the one with the 5G wifi network to the one with the 2.4G network. Simple. Just unplug the NAS from the first network and plug it into the second network. The 2nd network router will dynamically assign an IP address to it as 192.169.1.x and you’re good to go. You will be able to access it on your phone through the 2.4GHz wifi.

You can reserve and address on the 2nd router to your NAS using its MAC address or assign it a static IP address (the former is functionally the same but much easier). What brand/model routers do you have?