WorKDate Change Using Codeunit

Hi all,

      I want to change workdate in RTC in navision 2016 . when i run a codeunit i put a code for set the workdate like :


workdate := 010116D

and in RTC workdate is Different like this

so now, when i will run CodeUnit then automatically workdate is change according to my date(010116D) but it's not changed, why? 

In nav 2009 ,this things is possible.

Please suggest me how i can change workdate on RTC using Codeunit....