You can change this in the 'My Info' section of TurboTax. Sign in to your TurboTax account and click on 'Take Me to My Return'. You will have to choose 'Amend' or 'Add a State' to unlock your return if you have already e-filed and been accepted.
Click on 'My Info' on the left menu and select Edit (far right side of the screen) next to your spouse's name. You can change the occupation on this page. It is located underneath the SSN field. This entry is informational only, so you do not need to send in any amending forms if you make any changes to this field.