Think of all the places where your old email address resides, outside of your immediate control, waiting to give people plenty of false information. There are other people’s address books, old messages in people’s inboxes, websites that use your address as your logon name, and your business cards.

Changing your email address can be quite a chore.

1. Keep the old address for a little while

The first thing you need to do is check with your old mail provider and find out how long you can keep the old address and at what price. It’s probably worth the money to keep it for at least a few months.

2. Tell your contacts, but bcc: please

Then you need to tell everyone about the change. Using your new address, send an email to everyone in your address book—friends, relatives, and business associates. Address the message to yourself (again, with the new address), and BCC everyone else.

The BCC part is important. Providing everyone with everyone else’s email address is going to get people angry—especially if some people Reply to All.

3. Auto-forward and auto-respond

Set up your mail client to receive messages from both accounts. Check the client’s features to see if there’s a way to send an automated response in reply to any message coming from the old address—and only the old address. The message, of course, should remind them to use the new address.

You might also want to set up your client to separate messages by the Send To address. That way, you can really see who’s still using the old address.

For instance, if you use Gmail, you can create a filter that can move the message to a label (Gmail for folder) or put a star next to the message: