There are plenty of partition software utilities that will do the job. Aoemi is free,easy to use and works well. Unless I missed something, the built Windows Disk management is unable to change the System Reserved partition size at the beginning of a drive. Can't see any way off doing it. Windows disk management is very basic. I guess MS don't want users blaming them when they mess up their OS by playing around with anything other than basic functions.
Update:-
Having rechecked it, the problem is that Windows Disk Management is unable to free up space at the beginning of the drive, where the System Reseved partion is located. Therefore is unable to extend the System Reserved partition. Other partition software is able to do this.
Edited by deleted (Wed 05-Aug-15 12:55:34)