For links with round or flat pins, just force out the connecting pins with a tack or removal tool. Then, remove the links and reinstall the pins to lock them set up. Apple Watch Ultra is additionally appropriate with 45mm bands, but 45mm bands should only be worn for casual, https://finnyrjym.blogzet.com/the-basic-principles-of-watch-band-for-apple-watch-series-7-41421564