You cannot change it once its synced to the blockchain. You'll have to do this for future posts you would like to promote. there are also other means of promoting your content via tribes or front ends like steempeak or esteem that make it easier and more intuitive experience
You cannot change it once its synced to the blockchain. You'll have to do this for future posts you would like to promote. there are also other means of promoting your content via tribes or front ends like steempeak or esteem that make it easier and more intuitive experience