Stewart was disciplined by an Elite League committee over two incidents during the Giants away game against Cardiff Devils on Sunday 3 February.
He was handed a three-game ban for kneeing and another three-game ban for a check to the head.
The further three-game ban was as a result of the two serious match penalties in the same match.
But following a three-man appeals committee meeting on Thursday, it has been decided that the extra three-game ban should be quashed and the ban downgraded to six matches.
Stewart has already served part of the ban, missing the action against Nottingham Panthers last Wednesday, and will therefore be unavailable for the Giants' next five games.
Meanwhile, Friday night's game at the Odyssey Arena sees the Belfast Giants take on Coventry Blaze during their Pink in the Rink charity night.
Are you coming to Friday's game? Then make sure to support 'Pink in the Rink' and wear pink in support of Breast Cancer Care as the Giants take on the Coventry Blaze!
The Giants will be donning specially commissioned pink jerseys which will be raffled off after the game to raise funds for Breast Cancer Care.
"We are delighted that the Belfast Giants are supporting Breast Cancer Care's Big Pink Bucket Collection by wearing pink for their game against Coventry Blaze," Hannah Weddell, from the charity, said.
"Every 10 minutes, someone in the UK hears the devastating news that they have breast cancer.
"Every penny raised through the Big Pink Bucket Collection will enable Breast Cancer Care to continue providing free expert and professional support to anyone affected by this life-threatening disease."
She added: "We would like to say a huge thank you to the Belfast Giants and their fans for all their support with this campaign!"