Initiate workflow when field changes to anything

Use another field, start the workflow and use the "conditional action (if)" , there you can set a condition with your "Assigned To" field

Hello Jesse,

Do you want to send the notification when Assigned To column has some person: Then start your workflow on item start/edit: Put a if condition to check Assigned To column is empty or not. If it is not empty then use your send email action.

In case your requirement is like: Assigned To column data will be modified frequently. Eg: 1st this column is holding Person-A, this time we need to send email to Person-A. Item is edited, but not Assigned To column (means Assigned To column is holding Person-A but other fields are modified - this time you don't need to send email). Item edit has happened, this time Assigned To column also, so now it is holding Person-B. This time you need to send email to Person-B.

If this is your requirement then try the following:

Create a new column in your list (people type) - let us say named AssignedToCopy.

Start your workflow on item start/edit.

Workflow Logic:

Put a if condition to check Assigned To column and AssignedToCopy column data.

               If both are not equal (this means some one changed this from Person-A to Person-B) add send notification here. And also add                update item action and update the AssignedToCopy column with the same data as Assigned To column.

               If both column are equal that means item has been modified but not Person-A and you need not to send him email again. So                leave it empty this section.

I'm sure that method works fine.  There is a way to do this with a Condition without adding an additional field.  The workflow then becomes just one action - the notification. 

Set Start when new items are created to Yes and Start when items are Modified as Conditional. 

Use the Assigned To (Previous Value) item for comparison like this:

It will not fire a wf if other fields are edited but the Assigned To field is not edited.  Hope this helps!

Sorry, Jesse, my mistake.  I'm on-prem, obviously.  But this post led me to set it up the way I did in the first place.  I wasn't sure how to make it work without firing every time an item was edited.  Thanks for your help!

Yeah I saw that. Awesome! Thanks Muhammad