How do i apply for retainage on a job thats over 50% done which form do i use tks tim

it is now march 12th and im still waiting to get paid for work completed in january im about 90 % done on one job and about 75% done on another there both for the same gc and i would like to bring my retainage to reasonable percentage what form or how do i apply for the retainage i am useing the standard architects application for payment g702 and 703