I have a question. Could President Trump pick someone else to be Chief Justice?
Probably not, but he might find a way to expose Roberts as being corrupt and compromised, and cause Roberts to resign in shame.
what i find on line in quick search is the constitution doesn’t say it can’t happen, but since SC can rule about impeachments of presidents it is not a good practice to demote a chief justice or all presidents will likely start trying to rearrange who is chief justice to suit their preference when elected and their by nullify an important function of that part of govt.