800cc Gummy Implants - too big, please remove (Photo)

I am sorry to hear about your concerns after breast augmentation surgery.  You should be able to undergo downsizing of breast implants (without necessarily removing them first). Keep in mind as you are thinking about your goals that sometimes adjustment of the breast implant pockets (capsule adjustments) may be necessary to achieve the outcome you are looking for.   Whether or not the adjustment of the breast implant capsules will be necessary will mainly be dependent on your physical examination; specifically, factors such as the amount of redundant skin, quality of skin elasticity,  and how much you downsize will be important.  
Generally speaking, the best online advice I can give to ladies who are considering revisionary (downsizing) breast augmentation surgery is:
1. Concentrate on choosing your plastic surgeon carefully. Concentrate on appropriate training, certification, and the ability of the plastic surgeon to achieve the results you are looking for. Ask to see lots of examples of his/her work.
2. Have a full discussion and communication regarding your desired goals with your plastic surgeon. This communication will be critical in determining breast implant size/type/profile will most likely help achieve your goals. 
In my practice, the use of photographs of “goal” pictures (and breasts that are too big or too small) is very helpful. I have found that the use of words such as “natural” or "down a cup size” or "C or D cup" etc means different things to different people and therefore prove unhelpful.
Also, as you know, cup size varies depending on who makes the bra; therefore, discussing desired cup size may also be inaccurate. 
3. Once you feel you have communicated your goals clearly, allow your chosen plastic surgeon to work with you in determining the best plan to achieve your goals.
I hope this, and the attached link (dedicated to revisionary breast surgery, specifically downsizing breast augmentation surgery concerns), helps. Best wishes.  

I welcome you to contact our office for a consultation.  We have two offices in Houston and would be happy to speak with you to discuss and help you achieve your surgical goals.

You should in general be able to put in smaller implants without having to leave them out for several months - but I wonder if going down to 600s will be enough of a change to warrant the procedure? You should of course be assessed in person by a board-certified plastic surgeon who can go over all the various options with you.  And that may in fact be an appropriate reduction, but you should take a look at what 200 cc is (about 7 ounces but, in your case, only a 25% reduction) and see if that merits the surgery.  Whatever you decide you should (in general) be able to do this in one procedure.  I hope that this helps and good luck.  Dr. Alan Engler, Member of #RealSelf500