I do not want to file yet. I need to make changes

[Kat]

You don't have to e-file until you're ready.  You can edit any portion of your return until you've completed filing.  Just log out of your account and log back in when you're ready to continue.  See below for instructions to e-file your federal return using TurboTax.

https://ttlc.intuit.com/replies/3301375

[bmb0617]

It was rejected 3 times when I tried to efile so I made the mistake of selecting to file by mail and now I cannot make any changes

[Kat]

You should still be able to make any changes you need to.  Go back to the section(s) you need to correct and select "Edit" or "Update" beside the information you're wishing to change.  
A rejected e-file is as if you've never filed.