FritzBox 7362 sl OpenWrt reset

Good day!
I'm just installed OpenWrt on AVM FRITZ!Box 7362 SL using this instrictions , but when I wished to make static IP with gateway on another modem/router by configure network I used to be changing "WAN" section but I had changed "LAN" options( Now I can't tocontact with device over network(ethernet, wlan) . Can I connect with router or to put it in restore mod? Do You have any ideas?
Big Thanks!

@kubikrubit, welcome to the community!