It is the command clock set
See below:
switch (config) # clock set ?
<hh>:<mm>:<ss>
switch (config) # clock set 12:00:00 ?
<cr> Set the time but leave the date unchanged
<yyyy>/<mm>/<dd>
mti-mar-sx01 [standalone: master] (config) # clock set 12:00:00 2015/07/27 ?
<cr>
mti-mar-sx01 [standalone: master] (config) # clock set 12/00/00 2015/07/27