BOSTON (CBS) — Wednesday is the deadline for Massachusetts citizens to register to vote, allowing them to participate in the state’s March 1 primary–and it’s also the deadline to change parties, which Massachusetts Secretary of State Bill Galvin wants to bring to voters’ attention.

Galvin is concerned that many of the 20,000 voters signed up as members of the new United Independent Party may mistakenly believe they are able to vote in the primaries for other parties.

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“We’ve had a problem with this,” Galvin told WBZ NewsRadio 1030. “We’ve had over 20,000 of these folks that we’ve had to notify, that if you stay in that party, United Independent Party, so called, you will not be able to vote in any other party’s primary.”

He believes many of those voters may have meant to register as independent–or, as we in Massachusetts say, “unenrolled.”

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“You want to be an independent, ‘unenrolled,’ if you want to vote in party primaries without becoming a party member,” explained Galvin. “A Democrat, for instance, can’t vote in the Republican primary unless they change to unenrolled, a Republican can’t vote in the Democratic party unless they change to unenrolled.”

The United Independent Party gained official status in December 2014 after candidate Evan Falchuk won more than the 3 percent threshold for the United Independents to gain official recognition in that year’s gubernatorial election. The Green-Rainbow Party also gained official status.

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WBZ NewsRadio 1030’s Carl Stevens reports