In STEP7 Classic, there is an 'edit Ethernet node' which I think is the one you refer to.If the module already has an IP address, you can go to online access, find the device you want. Then online/diagnostics and there's a tab to change IP address/profinet name. This is in TIA.
There's a similar method in step 7 classic.
I am not 100% sure about this, but I think it is the same as Proneta or PST, the changed IP address does not remain when the power to the CPU is cycled.
edit: If you use the 'edit Ethernet node' to change a Profinet IO Device, other than an S7 CPU, then the IP remains.