There are different versions of the JBL Flip 6 with different tweeter connectors. Both require a slightly different disconnection procedure.

A connector next to the woofer connector, which can be disconnected just like the woofer's.

A spade connector with contact springs, which can be disconnected by simply prying up the tweeter.

To pry up the tweeter, insert the tip of a spudger between the battery connector and the connector stem of the tweeter and gently press the tweeter upwards to push the stems out of their contact springs.

To reconnect the spade connector, just press the contacts back into the springs.