You can always assign your service contract to another person, whereby the SIM card, tariff plan, the services you had enabled and customer account will stay the same. The ability to use TMCELL mobile network services passes to the new owner. You will no longer have control over his TMCELL customer account.
In order to assign your contract, visit your nearest TMCELL subscriber service branch together with the new contract owner (mandatory). Do not forget your passport and the passport of the new contract owner!