In the middle of entering content I discovered the length of 15 characters of a particular field I set earlier is not enough.
In Drupal6 I could change the settings of a cck field. It could be potentially dangerous, but in my case it's a lossless transform, I just want to make a maximum size of a field a little longer.
But in Drupal7 I get the message saying it's impossible to change the field settings because there is some content stored in that field in database.
This restriction seems too strict to me. A warning message seems to be enough.
So my question is what's the reasons for this behavior and what can be done in my case? Manual deleting and recreating the content is not the option.