When you load your route again on day 2 it asks “would you like to be routed back to the start”, if you select ‘no’ and continue to ride the route, it will figure out that you’re continuing on and provide directions accordingly.
Just be sure you know whicg direction you’re heading when you rejoin your path, because the computer will send you back the way you came if you’re not paying attention
I think this depends on what flavour of android you have. I can’t answer your question, but if you provide the phone model and os version, it should help whoever comes along and can answer :)