Hi @FMorris,

According to the translation of Google Translate, I think that your question is to reconnect the RE200 to new 6G router. If there is any discrepancy, please describe it in English.

Provided that the Wi-Fi name and password of your router stay unchanged, the extender can automatically reconnect after a restart. 
If you've changed your router or its Wi-Fi settings, you'll need to reconfigure your extender. Here's how:
    1. Use a pin to press the reset hole for 1-3 seconds to reset the extender.
    2. Reconnect to the extender's Wi-Fi and proceed with the setup.
You have three options for setting up your extender: 
    Via Tether app: How to Set Up TP Link Range Extender RE650 via Tether App 
    Via WPS button (If your router is TP-Link's product): Set Up TP-Link Range Extender via WPS Button (RE500X, etc.)
    Via Web browser: How to set up a TP-Link Range Extender