I have D-Link DIR-600M N-Modem. A day ago the WAN port got damaged due to lightning but the other ports still work. I can connect to the modem but the WAN port does not respond.
Is there any way I can configure one of the LAN port out of the 4 switch ports to work as WAN port?
My I.P provider provides a static IP address. I also use the modem as a WiFi hotspot.
No, you can't
The WAN port on that device is a routed port. It can have a different network address than your LAN network address and the LAN traffic would be routed through the WAN port to get to your ISP.
Unfortunately there are no Layer 3 ports on your switch side of the router.
You asked.
Is there any way I can configure one of the LAN port out of the 4 ports to work as WAN port?
No, there is not a way to configure one of your LAN switch port as a WAN port for your device.
