To get to the Merge Users panel, click on the following in the menu to your left: Users > Merge Users.
You can use the Merge Users panel to merge two users’ accounts into one (if, for example, one user registered twice).
<<<Screenshot of Merge Users panel>>>
Enter the username of the source user into the Source Username field. This user's data (as specified below) will be written over to the destination user. Permissions will not be transferred.
Enter the username of the destination user into the Destination Username field. This user will inherit the source user's data. They will not inherit any permissions from the source user.
Posts, threads, calendar events, and private messages of the source user will be changed to appear to have come from the destination user. The source user’s post count, reputation, buddies, and ignored users will be added to the destination user.
Permissions will not be changed and moderator status will not be transferred; these must be re-specified.
After merging the users, the source username will be available to be registered by another user after the time period specified by Username Reuse Delay setting in the User Registration Options panel.