Yes, you can merge two constituent records together on the constituent grid. On the grid, checkmark the two records you want to combine on the merge column. Then, click the "Actions" button. Under the "Actions" menu you will find the "Merge Constituents" button. You will then need to select which record you would like to keep and click the “Submit” button.
When merging two records only the following information will be added to the record you are keeping: email addresses, addresses, phone numbers, gifts, documents, interactions, relationships and events. Any other information that you would like to keep should be moved manually prior to completing this merge. The items that will move on the profile are highlighted in green on the Merge Records page.