Can I change feed back I have left from negative to positive

[cq_tech]

Absolutey, but you will need to contact your seller and ask them to send you a Feedback Revision Request. Once you've completed that, your negative feedback will be replaced by a positive.

[cherry*135]

Yes, you can, if it is your choice to do so ( not seller demanding it).

You will need to ask the seller to send you a Feedback Revision request first.