Apologies, I did not make that bit very clear.
For the BigFix Platform you will just need to stop the services, change the ‘Log on As’ setting, and start the services again. You can do this for all but the BES Client Service.
For Inventory/ILMT You will need to change the user in the server.xml file referenced in the link I shared. I’m assuming the passwords are changing as well. Depending where you’ve installed it, it will be under something like:
May be something like the following for ILMT:
You might also need to change your data source setting in the ILMT/BFInventory Ui
Management > Data Sources