Good practice for using both radios / going off frequency
Hi, say in the case of having a LARS/radar service but about to overfly or come close to airfield zone (but not enter it) and wanting to give a heads up to that zone (e.g. just to advise on overfly ETA and altitude) without leaving the LARS service (because it's still wanted after passing the zone), what is a good practice? Two options I can see, (1) request the service for a temporary off frequency to speak to the zone, (2) utilise second radio to do it (making sure to navigate the tx/rx audio panel switches). Can some more experienced pilots advise? I'm a relatively new PPL(A) on PA28,