You should just connect thorugh Console cable (using the PuTTY client, as example <-- check HPE OfficeConnect 1920 Switch Series latest documentation - User Guide - on how to do that) and then, once logged into the Switch Console, execute the ipsetup CLI Command (which assign an IP address to Default VLAN Id 1) once again or, if you really want to re-initialize, execute the initialize CLI Command (which delete the Startup Configuration file and reboot the switch into the factory default state).