There might be several reasons why you want to switch from one mobile provider to another. You can easily change your mobile operator, as there are numerous service providers in Switzerland. 
You can switch to another operator at the end of your contract or cancel it during the period. Also, you can port your existing number without paying the extra fees.

Usually, you have to visit a store to sign a new contract or use customer care to port your number to another mobile connection. Once your request is processed, your number will be ported to the new cellular connection within 1 to 3 working days.

Going with mobile portability would be the best option for you, as you don’t have to update your mobile number again in your bank, office, and other places.