How to change setting in SoftwareSerial.h file

Although I'm logged-in as Administrator in Windows 10, I cannot remove write protection and Windows do not allow me to make changes in the SoftwareSerial.h file. It calls for Administrator rights I already have???? Can enny boddy help pease??
(I'm aming at allocating more buffter for the bus).

SOLVED
By copy and paste via the dashboard, access to changing the file is accomplished.