The DUP is changing its representative on the Stormont commission, the cross-party body which runs the Assembly.
The move comes after the party blocked proposed reforms to MLAs' expenses system on Monday.
Stephen Moutray is becoming chairman of the Assembly's Agriculture Committee.
Sinn Fein has questioned why the DUP withdrew support at the last minute for a bill intended to pave the way for a new system of allowances.
The DUP said it was because for an interim period MLAs would have to vote on on their own expenses whereas the job should be done by an independent body which would not have been in place until 2011.
However, some people have asked why the party's representative on the Stormont Commission Stephen Moutray did not raise an objection before the bill had to be withdrawn just before it was due before the Assembly.
The BBC has learned that Mr Moutray is now leaving the commission to be replaced by Peter Weir.
The Upper Bann MLA will instead become chair of the Agriculture committee to replace Ian Paisley jr, who has left the Assembly after becoming MP for North Antrim.
A DUP spokesman said that with a number of MPs withdrawing from the Assembly the party was reshuffling its post-holders at Stormont to fill vacated positions.
He said Mr Moutray's move was a promotion. His salary will remain unchanged.