If you read the form 4 you will see that her sale was part of a previously established trading plan.
"1. The transactions reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on August 23, 2017"
Under Rule 10b5-1, directors and other major insiders in the company – large shareholders, officers and others who are able to access material nonpublic information (MNPI) – are able to establish a written plan that details when they will be able to buy or sell shares at a predetermined time on a scheduled basis. It is established this way so that the insiders have the ability to buy or sell shares when they are not in the vicinity of MNPI. This also allows companies to utilize 10b5-1 plans in large stock buybacks.
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