What brand is it? Rosemounts generally can be rezeroed at 14.7 and span set to 29.7 which would give you a 0 to 15 psig transmitter as long as you have a hart protocol communicator to reset the zero and span to read 4-20 from 0-30psig at the above settings, Rosemounts generally use the same pressure cells for a range of transmitters, we have 100 psg rated cells that we use for 0-30 inH2O that work just fine, look at the cell max pressure if it is over 30 psi then you should be able to reset the zero and span.
Even without the hart communicator most transmitters have a way to set the zero and span under the cap or under the slide away plate on the top, it will look like a aluminum spec plate with a rivets but one end will slide off and there will be push buttons or small pots to adjust the zero and span or they might be inside the from cover on the display side older Rosemounts were pots under the aluminum plate, look for a cap, plug or buttons marked zero, span or might just have a Z and S by it.
Also you might be able to order a 0-15psg replacement cell, I would talk to your suppler, the electronics are all the same for a range of cells you just have to have a hart communicator to reset the 14.7 psia to 0 psig unless it has buttons on the transmitter to program it.
At $160+ I would suspect it is not a Rosemount as they are much higher in price, normally I see them around $500 to $700
If you post the manufacture and model I might be able to look up the info you need?