Changing your current Apple ID

If you change your current Apple ID the easy way like it’s just a Alias id, or let’s say new Apple ID, will you still emails emails to that old Apple ID? That’s what I want to happen for sure.

I called Apple and they didn’t say anything about after you do that to delete your old Apple ID. So what is correct to do? I do not want to receive any emails to the old Apple ID. I am one of those who keep my me.com and iCloud.com original Apple ID. Do I have to delete both then or what? Can I leave them as Apple Tier One support said. I’m confused and when/if I change I don’t want any emails coming to the original Apple ID I want to change to EVER. Thanks for any help.