You are wading in water waist deep and you want to switch from a floating to a sinking tip line. Just remove the spool from your reel and replace it with the spool in your vest which is holding the sinking tip line. The problem is how to safely string up your 9ft. fly rod without wading back to the bank. To achieve this I thread up the lower half of the rod then take the rod apart at the middle ferrule and thread that part and reassemble the rod when I’m finished.
When putting your fly reel away for the winter clean inside the back plate, drag and spindle with a cleaning fluid and a Q-Tip unless the reel manufactures directions specify not to clean and oil it. On other reels apply a light coating of oil or reel grease to all working parts, being careful not to overdo this and get it on the line and backing. Set the reel in a shaded well ventilated area for several weeks to be sure the line and backing are completely dry, then store if for the winter.