How do I change all occurrences of one label to another? From the Gmail screen I can do this for the 100 messages displayed, but I have several screens of messages.
In a traditional mail program, I would say I'm trying to move all messages in one folder to another.
Best Answer
Go into Label A and click the checkbox within the Select button to select all of the messages on the page.
Look above the first message but below the action buttons, and you should see a notification that reads
All 100 conversations on this page are selected. Select all [X] conversations in "Label A". The second sentence is a link....Click the link in the notification, and all of the messages you have in "Label A" should be selected, including those beyond the first page. (The notification will change to reflect this.)
Click the Move to button---with the folder icon---above the message list and either click on "Label B" or, if it does not yet exist, click Create new below the labels list and enter "Label B."
Alternatively, you can use the Labels button to add Label B to your messages on top of Label A or give your current Label A messages any combination of labels.