Product Downgrade Procedure Query

I am changing to Antivirus Plus this year since I have a very solid hardware firewall which passes every known test I can subject it to. So having tried out Antivirus Plus for a while I have decided it is suitable for my needs.

The question I have is quite simple and will probably result in a yes/no answer.

When the BDIS license expires, will a currently installed copy of Internet Security be able to automatically be able to switch to Antivirus Plus if I enter my purchased Antivirus Plus key?

If not, I know what to do to clean up properly before installing AV+.

Thanks for any guidance on this.