It can be done, but it takes preparation... if just overnight/a few hours of below 32, easy enough, but if prolonged or HARD freeze - more prep...
Some rv's have '4 season' packages including more insulation and heating pads for holding tanks.. many do not though.
Some use something like
this, some turn off all outside water and drain the lines (including sewer), some just put put potable antifreeze in p-traps and sewer tanks (not fresh!)
You must protect the pipes from freezing - either by full winterizing, draining all lines and blowing out with air, or put heaters/lights in the basement..
You MUST turn on your furnace to keep temps above freezing - NOT electric heat/heat pumps as they won't warm basement...
good luck and if you are just asking this... I hope none of your pipes/connections/fixtures have frozen already. you'll find out the first thaw and it's part of the learning curve.