Read this support article about what to do if a iPhone or iPad is lost or stolen -->
If your iPhone or iPad is lost or stolen - Apple Support
- The Find My service described in the article is the only recovery feature Apple offers. It must be set up before the device is lost.
- Note that if you remotely erase your device as instructed in this article, if you subsequently remove it from your account as in this article --> Check your Apple ID device list to find where you're signed in - Apple Support , then according to this article --> How to remove Activation Lock - Apple Support you remove activation lock from the device. Do not remove it from your account. If you do then a finder or thief will have an unlocked device that can be used by another person.
I am guessing this is what it means by "pending" - your phone hasn't been able to receive the lost mode instructions --> If Find My iPhone is offline or not working, read this Apple Support article to get help; e.g., when you don't see your device listed, or you see an unexpected device or an alert that says your device is offline. --> If Find My is offline or not working - Apple Support
Changing your password will not affect Find My services.