Writerly question - corporate law division (I think)

[wood_dragon]

Assume a small company sold shares to raise capital at some point in the past. Now they want to buy out the shareholders. What (if any) recourse would a company have if someone refused to sell? Could they declare the shares worthless? Sue? Just have to deal with someone having a small piece of the business?

(Assume US. Assume no expiry date on the shares - so to speak.)