What impact when re-active license at 30/05 and after manual change time to 28/05

Hi Hoang_Hung , 
Q) If you are asking if Re-activating license on bigip cause production impact ? 
A) Yes it Causes impact and interrupt the Production traffic according to this Article from F5 : 
https://my.f5.com/manage/s/article/K35783352

But unfortunately I don't understand the part of changing time from ( 30/05 ) to ( 28/05 )