To change the selection of whether or not you can be claimed as a dependent on someone else's return (example: your parent's):
From within your TaxAct return (Online or Desktop), click Federal (on smaller devices, click in the top left corner of your screen, then click Federal).
Click the Basic Information dropdown, then click Dependent on someone else's tax return.
Continue with the interview process until you reach the screen titled Can you be claimed as a dependent?
Check or uncheck I can be claimed as a dependent on someone else's return to add or remove your exemption (i.e. to indicate you are or will be claimed on someone else's return).
If married, check My spouse can be claimed as a dependent on someone else's return as needed.