How to alter attributes in collections

Hi there, unluckily I made avatar as string. I should have make it URL. I forgot. Now my URLs for avatar coming more than 156 char. For hot fix, I need to use link shortner. How can I change the data type or increase the character limit in existing collection.

You'll need to create a new attribute, copy the data if required, and then delete the old attribute. You cannot update attribute size and name unfortunately.