I found my lost device can I reactivate it ?

Hello,

Yes, see this:

Turn off Lost Mode on an iPhone, iPad, iPod touch, or Apple Watch. In Find Devices on iCloud.com, click All Devices, then select the device that's in Lost Mode. Click Lost Mode, click Stop Lost Mode, then click Stop Lost Mode again.

For more detail:

Use Lost Mode in Find Devices on iCloud.com – Apple Support (UK)

Good luck.