Yes, it is possible to reposition a slide after it is created. Make sure you are inside your Interactive Deck Editor, follow the below steps to reposition your slide

Step 1: Go to Home tab inside your deck editor.

Step 2: Switch to ‘Sorter’ view in the preview section from the ribbon.

Step 3: This will replace the ‘Mobile’ view in the left to ‘Sorter’ view

Step 4: Now drag the slide, and drop it at the position you want.