Transform is read-only C# property. I guess it could be defined pretty most this way:
public Transform transform{get;private set;get;}
So, you can't assign directly a Transform to another Transform (you don't have set accessor defined).
You are forced to assign individual fields of each Transform to the other.
For example:
myscript.gameObject.transform.rotation = otherScript.gameObject.transform.rotation;
myscript.gameObject.transform.position = otherScript.gameObject.transform.position;
...