Just read this article in LOL.
Quote...
"According to the SGK office in Fethiye the following changes have been made:
Item (d) of the first paragraph of Article 60 of Law No. 5510 stipulated that expatriates who have received residence permits on the basis of reciprocity and who are not covered by health insurance in another country would be considered under the coverage of general healthy insurance.
By virtue of a recent amendment to the law, the general health insurance, which was obligatory previously, has now become voluntary.
If you were a holder of the general health insurance previous to this amendment and do not wish to continue paying premiums, you can apply to SGK in person and have your registration cancelled. However; if you wish to maintain your present status, you do not need to take any action.
Land of Lights will publish a full analysis of these changes in the next issue, following an interview with the manager of the SGK office...." end quote
This reads, to me at any rate, like you don't need to sign anything if you are in and happy about it.