On the TenX Wallet app, each cryptocurrency is stored in its own wallet.
Only one wallet can be set to primary at any one time.
The primary wallet set will show "My primary wallet" at the center of the main screen.
Using the arrows at the sides, scroll to your desired currency.
Each currency page has its own "Set as primary wallet" button in the center.
Tap on the "Set as primary wallet" button once you have scrolled to your desired cryptocurrency. The text on the button should change to "My primary wallet".
This will unlink the wallet that was formerly linked.