What 'tax liability" are you referring too? I'm going to guess her options are under the 'incentive stock option" rule because of her position so there should be no tax considerations until she trades them. On the other hand if she did sell them instead of holding them she would have been taxed at ordinary rates for the gain using a base of $8.70. The $8.70 would be deducted from the sale.
Her only obligation would have been to pay the $8.70 per share at this point.
Revance announces departure of CFO, CBO Lauren Silvernail Revance Therapeutics announced that Lauren Silvernail has resigned as Revance's CFO and Chief Business Officer, effective as of May 29, 2018, to pursue a CFO ole at an aesthetics company in Orange County, California, where she resides. Her departure is not based on any disagreement with the company's accounting principles or practices, internal controls or financial statement disclosures. Following Silvernail's resignation, certain members of management and the company's existing finance team will assume the duties and responsibilities of the office on an interim basis. Revance is initiating a search for its next CFO, who will play an important role as the company prepares for the commercialization of its lead product candidate, DaxibotulinumtoxinA for Injection.