Question : how to uninstall dot net framework 3.5 service pack?

how to uninstall dot net framework 3.5 service pack?
I want to uninstall dotnet framework3.5 service pack.
while I click the change/remove button in add and remove programmes selecting dotnet framework 3.5 service pack, It goes to installation.
I want to uninstall that.
what to do ?
I have no dotnet framework3.5  compack disk.
what to do ?

Answer : how to uninstall dot net framework 3.5 service pack?

what is your os?