Entity Context Error : - An entity object cannot be referenced by multiple instances of IEntityChangeTracker.

I've called a method to Extract a data for example person.
Here I didn't user "Using" for entity object creation.
I've sent this extracted data to another method to update.
There I'm using "Using" keyword to created Entity object .
My Actual Problem is  When I Update or Create data (context.SaveChanges()) , I got the error that "An entity object cannot be referenced by multiple instances of IEntityChangeTracker."
Because of what, I got this error ? and How to Solve this Error. Please tell it in simple way. I already got more link . I couldn't get what i need.
Thank you,
Jeeva J 
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