Hello,
Please do not modify the IPs in the database directly as this could cause unforseen issues and is not supported.
Meanwhile there is a way to change the IP addresses of your devices directly in iMC wihout deleting and re-adding them. I'm not sure on which version it was added, but if you are on one of the latest (7.3 E0705+) it should work:
1. Open the file iMC\client\conf\commonCfg.properties in a text editor, and change enableIPModification=false to enableIPModification=true
2. Restart jserver process via DMA. The option to modify the device IP will now be available on Device Details.