Expect sudo - comand

Question

This is piece of expect code with mistakes. In a few words, I must connect to the first server, and then jump on the second server, make su - to enable changing the data on this server, all using expect.

spawn ssh -J  root@$GATEWAY_ADDRESS litp-admin@$HOST_ADDRESS
   expect "assword: "
   send   "12shroot\r"
   expect "assword: "
   send   "12shroot\r"
   expect "~]$ "
   send   "su -\r"
   expect "~assword:"
   send   "12shroot\r"
   send   "date -s $NEW_DATE_TIME\r"

What are the possible solutions or examples?

I have not found the right solution.