Create the backup (export):
crontab -l > /some/shared/location/crontab.bak
Import it from the new user:
crontab /some/shared/location/crontab.bak
Create the backup (export):
crontab -l > /some/shared/location/crontab.bak
Import it from the new user:
crontab /some/shared/location/crontab.bak