I'm not an expert but could provide one based on my experience as I'm NOT building a lead form but something else and zaping it into a database.. If the user is engaged and begins entering in his/her information, the values get stored in variables.. however, if the user goes away there is a time out period.. (which you set in chatbot settings) the setting there determines the length of time the user has to continue (again not 100% sure I'm right here).. if the user comes back within that period, everything should be ok.. but if the user goes past that time, he's gotta start over.. I mean, there are limitations to right.. I mean your user can't leave for 24 hours then come back..