How should companies change their business plans to cope with a coronavirus pandemic?
I would be careful what type of business I would launch during this virus as it is like learning to swim and your first swim will be a trip across the Atlantic. Unless you have a business that the virus prompted and will be sustainable when the virus is gone (example: facemasks are a good business now but I hope not 2 years from now).
The goal of a business plan and accompanying startup is to build a sustainable enterprise that is profitable. This virus brings challenges to that so you will make whatever changes are necessary.