If the weather at the airfield in question doesn't prevent another approach using a ILS, VOR or Visual procedure, that is likeky the simplest way to go. However, I do get a sense that you might also be querying what to do if options are pressured due to things like diminishing time (fuel!), changing weather, and/or lack of suitable alternative approach procedures. You then have to sift what your aircraft and company operations manuals expect you to do in the circumstances, along with any differing (more restrictive) regulations in the country you are attempting the approach and landing. It could have potential to quickly become administratively untidy!
Sure, ask on frequency if anyone else has reported issues due to UNABLE RNP. As you say, it might already be obvious if others are talking about it. But was it a relatively short aberration, that has now corrected itself, and can you now trust the equipment to perform as intended? Much will depend on the known rules, plus the external influences that may have painted you into a corner, and your obligation to get crew, passsengers and aircraft safely on the ground. The joys of Command!