There was an identical topic created in this forum before. You should always take a look at previous topics before creating a new one - it may help you find your answer quicker!
Your scenario can be achieved by following this pattern:
1. SMS \ Call Settings tab -> set up two different(for example (a) and (b)) phone numbers to "GSM Predefined Numbers" list.
2. Features tab -> Alarm -> Send SMS To -> select first phone number (a)
3. Keyboard tab -> Alarm Button -> Set "1 Click" to "Alarm"
4. Keyboard tab -> Alarm Button -> Set "2 Clicks" to "SMS"
5. Keyboard tab -> SMS Action -> select second phone number (b) and type any SMS text (for example: Alarm!) to "SMS Text" field.
By following these steps, after you click the alarm button once, you will be notified about the alarm event to your phone number (a), by clicking the alarm button twice - you will be notified about alarm event (with configured SMS text content) to your phone number (b).