How to change/remove BIOS splash screen on Lenovo B460e laptop?

Change it? Very doubtful. Also, as a government IT guy, i would recommend you leave the bios of a computer of that nature alone. I doubt your IT team would like you to go poking around with it. Sorry if this doesnt help.

In that vein, the only change that you will most likely be able to do with a business class laptop, is to remove the bios screen itself, and go straight to the verbose style post screen (shows the memory count, bios version, boot status, etc.)

Generally OEM manufactured desktops and laptops won't provide a utility to replace the splash screen, but this isn't uncommon with standalone motherboards that one would use when building a PC.

It's possible to modify and reflash most BIOSes but you need to know exactly what you are doing otherwise you risk an unbootable system. Mods are out there but it's very risky to attempt any of this.

OEMs generally purchase a BIOS toolkit from a BIOS provider (Phoenix, etc.) and then use said tools to customize the BIOS. It may be possible to acquire such utilities (probably not legally) but it is equally as risky as above.