Yes you can.
We recommend that you first connect the earbuds to your chosen device as a pair.
Once set up in stereo you can simply remove each earbud individually from the case and use on their own.
To use them in stereo again, you would just need to remove the other bud and they will automatically dual pair together.
If the earbuds do not automatically dual pair together when both are removed from the case, follow this guide to get them working in stereo again.