where is your layover ?
you mentionned New York, but is that EWR, JFK or LaGuardia ?
45 minutes is tight. And the airport you're connecting at might make a difference.
If you have to go to another terminal it might eat up all of your time.
Most travelers are not comfortable with a connection that's under 60 minutes.
Do not attempt this connection IF you travel with 2 separate carriers. For example if you have 2 separate tickets.
If you're on the same ticket/same carrier, if you miss your connection you'll be booked onto the next flight. If not it's your loss.
I have a 61 minutes layover in PHL in november and I consider it to be a bare minimum (I even think it's gonna be insufficient and I'm trying to get this changed)
You can attempt this itinerary if you manage to be seated at the front of the plane, to deplane as fast as possible.
If you have mobility problems or need to gate check a stroller, it probably won't be enough time (might as well put it as checked baggage)
But I also wouldn't want to check baggages at all, as if your plane is late, and even if you manage to run like hell and catch the next plane, your suitcases might not follow. To be on the safe side I would go with carry-on only
With kids it might be painful (depending on the airport, terminals and how much walking/running is involved)
Anyway, if the airline says it's a legal connection then it must be possible to get that flight.
Sorry, I'm just thinking out loud, it's because I face the same kind of question.
Also make sure that there is no fee linked to any flight change.
Changing to the 45mins flight connection was free because your initial flight was discontinued, but now if you have a non refundable/non exchangable ticket, it might be another story. Just ask your TA
45 minutes is real tight
but 5 hours in New-York is a nightmare ...