I think this is dependent on your reporting and overall architecture of naming in the system. There are a few big buckets you might be sitting in, so I'll try to provide an approach based on this.
1. You are tracking by date of send and Quarter
If this is the case I would clone your old email create a new campaign with the name updated based on the date and Quarter of the new send and set up your A/B test. Make sure you are sending the same day of week and time of day otherwise your data might shift dramatically based on those factors rather than your new test.
2. You are tracking based on asset type not Quarter/Date of send
If this is the case I would add onto your already existing program. By creating new emails with your new tests, a new smart list and new smart campaign with flows. You could then create a local report inside of this asset to track it or use campaign reports to see how this CTA results pan out.
Other items you want to think about: who are you sending this next batch you? Your same smart list just those who weren't a part of the original smart list due to natural growth of your database? The same smart list but just those who didn't open the first time? Based on this you may or may not need a new list to target off of and could affect how you construct the list and send components.