What it does is it clears the memory buffers of the internal memory of the APOS unit. However, if this is performed during a transaction, the transaction itself will be lost.
Soft reset should only be performed if you're experiencing performance issues, such as slow response times while in the GoPOS software, or in cases where the APOS system freezes or crashes.
To perform the Soft Reset, ensure you're logged in as a user with programming privileges enabled.
Next, from Register Mode, tap on the Home button. Then from the Home Screen, tap on Menu > Settings > Soft Reset. A warning prompt will pop up stating that it will clear any open transactions. Accept and after a moment, the buffers will be cleared.
If you are experiencing issues booting into the GoPOS software, please see our FAQ article here on how to to boot into Optima GoPOS without going into Register Mode.