Writing expressions in orchestration

Hi,

I want to use decide shape in my orcheatration. If I don't promote a field in schema I am not able uses the field in expression.
Is it mandatory to have distinguished fields inorder write expression. Is there any other method to write expression without have to promote the fields

Thanks in advance

You can use local variables in an expression.

You can use message context properties, both your own and the standard Biztalk properties.

You can use Distinguished fields.

You can use the xpath function for reading and writing the message directly.