It’s possible using eclipse debug perspective to disconnect from a debug process.
After this, is it possible to reconnect Eclipse debugger on this process ?
You can disconnect using the “Disconnect” toolbar button in the Debug view (looks a bit like a horizontal red lightning bolt!).
To reconnect, change to the “DDMS” perspective, select the process you’d like to (re)connect to in the “Devices” pane and click the green “Debug the selected process…” button at the top of that pane.