If it's just a couple of pins you can change any pin name by double-clicking the pad to open the Properties dialog box, change the pin number and select OK. In the V2014.12 release you will be able to select the "Enter" key to close the Properties dialog box (right now you have to select the "OK" button to accept your new pin number).

If it's a row of pins, you might want to get the coordinate of the first pin and write it down and then delete the row. Select the pad stack, enter the coordinate, pin qty, pitch and correct pin number to replace the row. It's rather fast to re-insert pins if they're in a row.