How to change field type if the field is referenced? 

Hi Saddam,

There are two ways to get this done that I know of. Assuming you're working primarily in a sandbox:

• Comment out all the lines with that field in it in all classes and triggers.
• Modify the field.
• Deploy all the changed code and metadata to production
• Uncomment all those lines of code
• Deploy all the changed code to production

or

• Make a new field with a new name.
• Change every reference in your code to that new field.
• Deploy changed code and new metadata to production
• Move over any data from the old field to the new field