Reported mi iPad lost but I found it and now I cannot take out of "lost mode". Please advise on what to do. Thank you!

If you used "Lost Mode," according to: Use Lost Mode in Find My iPhone on iCloud.com - Apple Support you had to setup a passcode to activate Lost Mode.

• Passcode: If your iPhone, iPad, iPod touch, or Apple Watch has a passcode, it’s required to unlock the device. Otherwise, you’re asked to create a passcode now. If you’re locking a Mac, you must create a numerical passcode, even if you already have a password set up on your Mac. This passcode is distinct from your password and is only used when you lock your Mac with Find My iPhone.

if it has a passcode try to open it as you normally would and enter the device passcode