In Weebly, an app can only be connected to a single website at one time. If you need, you can move your scheduler from one site to another in two steps: (1) Remove and (2) Add.
Step 1 - Removing the Schedulista app
Removing the Schedulista app from a Weebly site will disconnect your account from the site, freeing it up to be connected to the app on another site.
(1) Sign into your Weebly account and edit your site
(2) Click on Settings in the top navigation bar
(3) Select My Apps from the menu on the left
(4) Locate Schedulista on the Installed Apps list and click the More (...) button
(5) Click on Remove App from the menu
(6) In the Remove App dialog, click Yes, remove
(7) When prompted after the app has been successfully removed, click Reload
Step 2 - Add to your new site
Now that the app is removed from your first site, disconnecting your account, you can add Schedulista to your new site through the App Center.