How to enable merge option for a user in leads?

[sujithraalink]

How to enable a merge option for a user in leads to remove duplicates? Admin can perform this action. but user with other roles can't do it.
His Lead permissions are (Create -yes Read-own Edit-own Delete -no Stream-no). Please help me.

[yuri]

User should have an access to delete records. Merge = update 1st record, delete 2nd.