About to buy a new handset and would really like to have work and home sims in the same phone. The Galaxy 24 seems to have a dual sim tray, but how do calls work? Do you have to swap between them or can both be on standby for calls at the same time? I appreciate that if you're taking a call on one you won't be able to take a call on the other as well obviously, but it's more about whether both are on standby for calls at the same time.