New to the forum. I saw this post and not sure if this addresses all of my concerns. Newer Admin to a existing 2013 on-prem environment. IT has asked that all the Service Accounts for SharePoint be changed. (example: current account "SPContent_SvcAct" would be replaced by "SVC_SPContent" and so on for all the current SharePoint Service Accounts.)
IT has already created all new accounts - 'mirrored' profiles from previous existing service accounts. The new accounts will replace the exiting Service Accounts during a cut-over, and then the old ones will eventually be removed after a period of time.
I have not found anything outside of 'creating' new accounts, save for one article addressing it in for SP 2010. I'm looking to see if anyone has had to do this previously replace account to an existing environment?