Change time format of "User" account

Change time format of "User" account

Hello,

We use Wyse z90d7.
I changed the time and the time format of the administrator account succesfully. But the time format of the "User" account is still in 12H format. As this account is locked from changing any time settings, how do I display the correct time format?

Thanks in advance.

Regards,
Jelle