From monthly to annual subscription

Hi everyone/Staff and Admin. I’m a satisfed Italian user of XERT, (sorry for my bad English, but i not love the transaltor…). Actually, i have a monthly billed subscription and i like translate in the Annual billed subscription, so, for this passage, what is the procedure ? Thanks in advanced for support, have a good :biking_man: ride ! Sincerely,
Corrado.