An Irish FA statement said the Linfield manager's ban had been "upheld" but due to "mitigating factors" had been altered to a "two-match suspension".
The sanction will now start on 11 April with the other two-match ban suspended for six months.
The ban was imposed after Healy's red carding at Portadown on 12 February.
Healy was furious after referee Arnold Hunter awarded the Ports a controversial penalty which helped clinch a 2-1 win.
Linfield go into Saturday's Seaview contest five points behind the leaders and current champions in the first round of fixtures since the Premiership split.
David Healy will be in the Linfield dugout for Saturday's crucial Irish Premiership game against Crusaders after having his four-game ban reduced.