Is it possible to convert a propane grill to a natural gas? ?

Conversion kits are readily available. You probably don't need to change out the burners, just the jets that meter the fuel.

I used a propane grill hooked to a gas line for YEARS until the stand rusted.  Then I  bought a new one and a conversion kit that took about 1/2 hour to install.  I don't remember how many $ it cost. The "orifices" for nat gas are larger b/c nat gas does NOT burn as hot as propane, so the flame needs to be larger to help out.  Nat Gas means you NEVER run out of gas when you're cooking AND it's close to free.  (not free, but cheap)  Wood / charcoal is best but expensive and a pain in the ***. Propane is good, but expensive and you have to drive to buy it.  Nat Gas is SO easy and cheap.

no propane uses different jets than LPG  and the btu is different in the gases . And they have different hose connectors .

It is POSSIBLE. The primary difference is the size of the holes in the burner the fuel comes out of. MOST burners are designed for one or the other. A few are adjustable. Unless the grill you have was designed to be converted, you would probably need to replace the burner.

A conversion kit would have to be made for your specific grill, because not all grills use the same size burner.

ask the maker ... if it's possible, they know and may have a kit available to do so

according to this sites question an answer section your model can't be converted.   It is propane only.  

In 2 or 3 years when that one rusts out get a webber you won't regret it there worth the extra 100/200 bucks.  they last longer an cook better than any other grill.

Their website lists a natural gas conversion kit for the 3 Embers grill. It's $100.  You will also need to have a gas line run to the grill area.

Go to their website and see if they offer a conversion kit.

I have eaten meat from 'gas' heated ' grills. There are weird chemicals in propane AND natural gas. I would burn hickory chips to get great flavor. 

You have to replace the gas orifices in the appliance. So, it depends on the appliance, if they make the orifice removable and replacable, you can.