On the banner to the right of the Wikitree page, go to ADD then MATCHES & MERGES.
In the two boxes include the surname followed by the profile ID. Highest into lower.
Now merge, and then following a comparison to ensure you are totally happy, propose the merge. Should you be the manager of both profiles or the profiles are open, you will be able to complete the merge by following the page instruction.
If you are not manager of both profiles the merge will await both profile managers consent, before the merge can proceed. If after 30 days, both parties have not given there consent, default approval is granted and again the merge may proceed.