Nomad
Master Black Belt
I would do as my instructor does... tell the new students that it's great that they went so far in their previous school, but that you need to evaluate them, and that you likely have teaching differences, etc. to the other school. Ask them to wear a lower belt for now (probably not white since they're not a beginner... green maybe?), and let them know that they need to cover certain parts of the syllabus to truly earn the belt they're wearing. If they are knowledgeable in the techniques and have a good attitude, they are likely to be promoted fairly quickly.
This way, they don't feel like they're starting over from scratch, and you have options based on your observations of what they know and what they need to know to earn the rank.
This way, they don't feel like they're starting over from scratch, and you have options based on your observations of what they know and what they need to know to earn the rank.