Purchase Receipt Enter Wrong and ti be amend

Hello Everyone,

I have created purchase receipt in Jan-2019 and record the invoice for the same. As it was AED purchase, i enter the rate 0.825 instead of 0.0825. Upon reviewing we found this mistake and we change the purchase receipt with actual rate in.

As we change the purchase receipt with previous date the item cost has been not change for the previous sales transaction.

So how to correct purchase receipt of item where sales transaction related to this item should be change automatically.