modify a restart file

[gossaral]

Hi!
I am running WRF over a snow-covered area. I have run a year of simulation and would like to re-run the same year with some adaptations. As the snowpack need a while to reach equilibrium from the beginning of the simulation, I would like to overwrite the snow variables of my first restart file (beginning of the year) with the ones of the last (end of the year). Is there a way to overwrite certain variables in the restart file? Or, is it possible to modify the date/time stamp of the last restart file to give it the date of the beginning of the year?
I tried to modify this but wrf.exe stopped as it could not read in the restart file.

Thanks a lot!