Q: ICloud Storage

You don't have to do it from any particular device.

iPhone, iPad, or iPod touch:

1. If you're using iOS 8 or later, go to Settings > iCloud > Storage. If you're using an earlier version of iOS, go to Settings > iCloud > Storage & Backup.
2. Tap Change Storage Plan.
3. Tap Downgrade Options and enter your Apple ID password.
4. Choose a different plan to use when your current storage plan expires.
5. Tap Done.

Mac:

1. Choose Apple menu > System Preferences, then click iCloud.
2. Click Manage in the lower-right corner.
3. Click Change Storage Plan in the upper-right corner.
4. Click Downgrade Options.
5. Enter your Apple ID password, then click Manage.
6. Choose a different plan to use when your current storage plan expires.
7. Click Done.

PC:

1. Open iCloud for Windows.
2. Click Storage.
3. Click Change Storage Plan.
4. Click Downgrade Options.
5. Enter your Apple ID password, then click Manage.
6. Choose a different plan to use when your current storage plan expires.
7. Click Done.