How to bend your ring finger for guitar?

You know how.. You grab B major on guitar? Or A or any other chord that allows you to use your middle+ring+pinky finger? Well if you grab a higher fret chord, it becomes harder to grab those chords so you need to use your ring finger to support three guitar strings. Well.. My ring finger doesn't bend enough and it keeps muting the guitar string. How do I bend my ring finger more? Thanks