When a person finishes a sentence and then decides to add "clarification" in the form of an appositive that renames the subject, the only correct punctuation is a dash.
...We didn't have the expertise to do that kind of project -- my husband and I.
...They came in quietly and said nothing during the meeting -- the supervisors.
...It is what we need to do -- review the entire file.
...This is what I would like -- to go to see him in person.
...That is what he was referring to -- that the project was away over budget.
...That is the important thing -- that she be in good shape for the tests.
Happy punctuating!
Margie