You can go to that person's profile in the People tab and click on Edit Profile and try to correct the email address there. If the wrong email address hasn't been confirmed by anyone you should be able to do this.
Note: If you removed the PTA member profile from the org, you can add it back by going to the People tab, Add Person page. There enter the name and incorrect email address and submit. The system will ask if you want to reactivate that person. Click yes.
If the person has a profile already with the correct email address and now has a PTA member profile with the wrong email address you'll need to move the correct email address. The system won't allow two profiles to use the same email address.
To do this go into the non-PTA profile, click to edit profile and cut the email address. Save. Then go into PTA profile, click to edit profile and paste the email address there. Save. Then go back to non-PTA profile in People tab and check the profile, go to People Actions dropdown and click Remove from Org.
Note: This will only work if the correct email address has not yet been confirmed. If the correct email address has already been confirmed then you will need to submit a support ticket to firstname.lastname@example.org so we can correct it in the database.