Can I downgrade to plus

Why do you want PLUS?    PLUS is Free Edition with some added benefits for 19.99.  See this FAQ:

https://ttlc.intuit.com/community/choosing-a-product/help/what-s-included-in-plus-help-tools/01/26430

Is your return simple enough that you can use Free Edition and PLUS?  Whether or not  you can use Free Edition with PLUS depends on what all is in your return.  Free Edition is for very simple returns.   If you need any of the new Schedules 1-6, for instance, you can't use Free Edition (or PLUS).

You appear to be using Live Self-Employed now (199.99 for Federal; 44.99 for state).   If you remove the Live feature, you'll be in regular Self-Employed Edition (119.99 for Federal; 44.99 for state), unless you use "Clear and Start Over", which starts from scratch.    If you haven't paid or registered previously in Free Edition, you can downgrade to any edition by using "Clear and Start Over".

If you want to remove Live but stay in Self-Employed Edition, here's how:
https://ttlc.intuit.com/community/downgrading/help/how-do-i-remove-turbotax-live/00/27312

If you want to completely start over and choose a different edition, here's how:

https://ttlc.intuit.com/community/using-turbotax/help/how-do-i-clear-and-start-over-in-turbotax-online/00/26444