Hello Team,
This should definitely help you out.

Step 1- So the trigger is when an Item or a file is modified
Step 2 - Get changes for an Item or a file
Keep the configurations same as the one I have mentioned in the screenshot below.

Step 3 - Condition
Here the true magic lies, the above action gives you results for each column that might have changed in the form of true or false as shown below -

So you just need to grab the column that you are looking after in your case Product/Vendor and apply a condition to check if the response for modified of it is True or False, if it is true then it has been modified doesnt matter what it has been modified to.
Just starting writing your next part of logic in the YES logic of the condition.

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