The England centre-back almost joined Liverpool on transfer deadline day last month, but Palace pulled the plug at the last minute, missing out on a sizeable fee.
Glasner revealed the defender, in the final 12 months of his contract, has already informed the club that this will be his final season at Selhurst Park.
"The club wanted (him to stay). They offered Marc a new contract, but he said, 'No, I want to make something different', and that's normal," he said.
"And for us, it's how we can deal with this situation. (What) is the best way to get this next step done? And that's all about how we are talking together."
Guehi has played 167 times for Palace since he joined from Chelsea in 2021 and captained the club to FA Cup success in May. He has won 26 England caps.
The 25-year-old could be sold in January or leave on a free at the end of the season.
Guehi, who has been ever-present for Palace this season, can agree a pre-contract with foreign clubs from January 1.
Palace would reportedly like to sell him in January, and it is understood that Liverpool could face competition from Barcelona, Real Madrid and Bayern Munich.
The London club, who were sixth in the Premier League before the weekend fixtures after an impressive start to the season, host high-flying Bournemouth on Saturday.