String Variable length

For a string variable we need to adjust the max characters from 500 to 4000. We have  statements that must be a part of some of our documentation and they are well over 500 characters. Is there way to adjust the settings from 500 to 4000 on string variables or is there a better way to do it? I tried adjusting the constraints in the type and attribute manager but it would not take after I saved.  Any thoughts.