I am trying to create a custom rule so that when a draft document (attached to the task) is approved, it then will reassign that task to someone to finalise and send.
I have tried putting the whole task as an approval but then when it is reassigned and that person hits “approved” it creates an infintie loop of the same task to keep being approved.
I have tried putting the approval as a subtask, but then the attachment doesn’t stay with the new task that is created.
What do you mean by infinite loop? Do you want the rule to both re-open and assign to the next person?
Subtasks might be a good way, simply put the attachment in the parent task, would that work?
By infinite loop I mean the task is reassigned, then when the person to whom it is reassigned ticks it as “approved” (because there is no “Completed” option) it runs the rule again and creates another task to be approved. It just keeps going and going.
I have put the attachment on the parent task. It doesn’t move to the new one.
In cases like this you should consider using “pivot custom fields”, and use the value of this field as a secondary trigger to make sure you don’t re-trigger.
my sentence probably doesn’t make sense, let me know and I can record myself explaining
Sorry I don’t understand 
I think you should have a rule that says if an approval task is approved, then you need to re-open it and assign it to a second person, correct?
But, when the second person approves, you don’t want the rule to run.
So, the rules needs to change a custom field of type dropdown, go from a value like “Never ran” to “Ran at least once”. And then your rule trigger becomes “if task is approved AND dropdown is ‘Never ran’” + in the actions it has to change the dropdown value to “Ran at least once”.
The dropdown field is what we call a pivot field.
Does it make sense?
Yes it does, thank you!
After spending a few hours fiddling with this I think that a custom field for Awaiting Approval and Approved is a potential better option that the Approval - which, from everything I have read, really doesn’t seem to function the way users would logically expect it to as it closes tasks off. I’ve certainly learned a lot trying to work all of this out!
I am disappointed that it’s not possible to dynamically assign project roles through a rule, nor possible to generate a template task using a rule, so the task has to be manually created when setting up the rule. I see so many possibilities for automation, but also so many limitations (such as rules running on a project or section level, not at a task level - I don’t want a rule to run every time X value changes on any task - just this specific one). We use a lot of templates for our workflows so whilst testing Rules now we have a trial of a higher subscription is exciting, it’s equal parts frustrating!