I have a booking coming up for SJU-(UA)-EWR-(LH)-FRA with a 40 minute window to connect at EWR. I rarely fly through EWR and can't recall having ever transfered from UA to LH there. I understand that my UA flight arrives at Terminal C and my LH flight departs from B, how easy is the transfer given the limited time I have? I have TSA Pre if that is of any significance in this instance.