If your sub is set to run out on the 16th, it won’t charge until then. There isn’t anything you can do to change that date.
The only way that I know of would be to let the game time run out then resub on the date you actually want it start charging on.
Edit: To phrase it another way, you can’t manually make the system change your charge date. It will always renew when your game time is set to run out.