Reset phone w/ shared ID

Here are two extremes of what you could do depending upon how much new setting up and retention of old items you wish to manage.

What to do before selling or giving away your iPhone, iPad, or iPod touch"Use these steps to remove your personal information from a device, even if you don't have it anymore." Click here --> hhttps://support.apple.com/HT20824

Sign out of iCloud on your iPhone, iPad, iPod touch, Apple TV, or Mac --> https://support.apple.com/HT208242

It depends upon what you mean by resetting and what you mean by shared. Shared with another user, or just your ID on multiple devices owned by you?

Resetting either of these ways in bulk will not affect other devices. What would affect other devices is if you reset by going in and deleting items in each iCloud category such as deleting a bunch of photos synced to iCloud and other devices.

See these support articles:

Restore your iPhone, iPad, or iPod to factory settings [with a computer] - "A factory restore erases the information and settings on your iPhone, iPad, or iPod and installs the latest version of iOS or iPod software."

Click here --> http://support.apple.com/HT201252

How to erase your iPhone, iPad, or iPod touch

"Learn how to wipe information from your iPhone, iPad, or iPod touch and restore your device to factory settings." Without using a computer. Does not reinstall iOS.

Click here --> https://support.apple.com/HT201274

if you're ever uncertain about doing something, make backups first.

Correction:

The first URL I provided in my last response was corrupted: What to do before you sell, give away, or trade in your iPhone, iPad, or iPod touch - Apple Support