I suppose it's 401k account.
Log in.
Left hand side, under Act, click on Change Investments.
Click on Exchange.
Right hand side, under Related links, click on View pending exchanges.
First take a look at the Trade Data Trade Time of your particular order. If it's Jun 7, that's today. If it's Jun 8, it will be executed tomorrow.
Click on Details for that particular order, now you should see Delete pending exchange button.