Go to the People Page in your Dashboard
Tick the boxes next to the names you'd like to merge:
Select "Actions" and then "Merge"
Confirm that you've chosen the right people and select "next step":
If you realize that you've made a mistake, select Cancel.
Choose the first and last names and contact preference that the merged person will have and select "fix conflicts":
Review the changes you've made before selecting "Perform Merge":
Or, if you find a mistake and want to cancel the merge, select Reset your choices.