Removing/replacing a variant

[Davide Liessi]

Dear MacPorts developers,

one of the ports I maintain, Frescobaldi, has just removed support for
Python 2.6, so in the next update I need to remove the +python26
variant and replace it with the (default) +python27.
What is the recommended way to do this?
I found in the documentation how to remove/replace a port, but I could
not find the same information for variants.

Best wishes.
Davide