You can choose your tariff plan when activating your SIM card. When making the first call you will hear your current tariff plan. You can either confirm that or chose another one. You can change your tariff plan within 16 days up to 4 times for free without any need of additional recharge. Afterwards you will be able to change the tariff plan for free by just recharging your account with 1000 AMD or more and change the tariff plan within 24 hours.
Tariff plan can be changed by:

• dialing  111  1    on your Orange number
• calling 111   from your Orange number
• going to My Orange page 
• visiting any Orange shop and presenting your ID document.