I have a question. When I had my son in August last year I breastfeed for a month and switched to…

I have a question. When I had my son in August last year I breastfeed for a month and switched to formula. He will be 6 months on the 14th and I was wondering if you can go back to breastfeeding if you haven't been pumping or anything like that for 5 months (Reminder my son is going to be 6 months on the 14th).