Have they planned how?
Whether is a viable opposition remains to be seen. There are oppositions groups and individuals but whether they can manage the country properly may be a big unknown.
The greatest danger is a "power vacuum"; the country breaking down in fighting between factions pleased to see the Maduros taken away, even if they don't necessarily agree with a foreign country having removed them; and Maduro's loyalists including possibly the military.
Such unrest will serve no-one's interests, certainly not of the USA nor of the US oil firms hoping to take over Venezuela's main industry, and least of all the citizens of the country.
