I think if you are in a part 121 environment the only choice would be to burn down to landing fuel and land as soon as practicable. I think it's highly unlikely you can amend your dispatch release in such a scenario. The most conservative choice is almost always the one to make.
If you are part 135 you should consider what is the safest course of action for your passengers but you have a bit more discretion to make that decision. The end result usually determines the wisdom of your decision. Hindsight is 20/20 so to speak....if you survive and don't cause further damage or incident, your decision was sound enough.
If you are part 91 that logic extends a bit further.
Basically be prepared to be judged by the outcome....if you elect to burn down to landing fuel and land and lose the revenue from the flight you may be asked about why you didn't continue. If you continue to your destination, land, and collect the revenue from the flight but have stranded the airplane to the point it must now be ferried all the way back at high cost you will likely be blamed for wasting money too. If you continued a revenue flight that also brought you back to or closer to a maintenance base you may get a big pat on the back, a heroes welcome by management, and paraded in front of the other pilots as a shining example of a team player.
As far as the technical side of it....your FMS will probably tell you what your landing fuel will be based on the new airspeed and power settings or you can easily enough calculate it...don't cut yourself short thought. Some airplanes publish limitations on this and some don't...know your limitations and comply with them.
Basically use your judgement, this is what we get paid to do. And as I might point out...this is what sets an experienced pilot apart from an inexperienced one...it is also one of those moments that defines your experience.