Hi there,
Players can not have the Month Card and Season Card at the same time. You can upgrade the Month Card to Season Card before the Month card expires, which will cost you some money depending on how many days you've used the card. You can also choose to purchase a Season Card when the Month card is invalid.
If you have any further questions or problems, please reply on this thread or feel free to contact us directly at
support-panda2@snailgame.net.
Have a nice day!
Taichi Panda:Heroes Support Team