Call diversion, also called call forwarding, is a feature of your phone service that sends incoming calls to another number. There are usually several kinds: divert every call, divert when busy, divert when unreachable (the phone is off or out of signal) and divert when unanswered, which sends a call on after it has rung for a set time. For a salon owner the useful one is usually divert when unanswered. The phone rings as normal, and only the calls you cannot pick up go elsewhere.
Diversions are switched on and off with short codes dialled on the phone itself, or in your carrier's app. The codes follow a common pattern across carriers, but check yours, and check whether diverted calls cost anything on your phone plan.
In practice
A solo hairdresser misses about 6 calls a day while working. She sets her mobile to divert unanswered calls after about twenty seconds to an answering line. Over a six-day week that is 36 calls that would otherwise have ended at voicemail, where many callers leave no message. She switches the divert off for Sunday and Monday, her days off, so calls go to voicemail as before, and switches it back on first thing Tuesday.
Keep the off code somewhere you will find it. The most common trouble with diversion is forgetting it is on.
In Glow Line
On the Line and Salon plans, the Receptionist page shows the divert code for Telstra, Optus and Vodafone, and the code to turn it off. A call you do not answer within about twenty seconds goes to your Glow Line number, where the assistant picks up. See divert your missed calls.