How to remove a stuck captains seat base with out removal of the pedestal

[Knot a Problem]

I am a new to me 2019 21sx saltwater tritoon nice looking and I just down size from a 30 Proline center console. I want to replace the captains chair that is rusted very much it only moves front to back will not spin. very corroded. I know I would have to cut the seat off the base, any short cuts out there just to removed the stuck base off the pedestal? I live on the Gulf coast of Fl.

 

[Potomacbassin’]

The mechanisms are fairly simple, at least on many models. Springfield products. Should just be a series of nuts, bolts and screws to access the seat base with all the corrosion and go from there? Clean and lubricate or get a new base?