Former manager Ole Gunnar Solskjaer says there is “no magic wand” to fix the problems at Manchester United.
Sir Jim Ratcliffe has bought a 27.7% stake in United, who lost 3-1 at Manchester City on Sunday.
It was their 11th defeat in the Premier League this season and left Erik ten Hag’s side sixth in the table.
“With Erik, I hope he is going to be successful. I hope he is going to make it but you never know what the new owners are thinking,” said Solskjaer.
“It’s about results and consistency the rest of the season.”
Ratcliffe will oversee the club’s footballing operations, but the Glazer family remain as majority owners.
The British billionaire called for patience from fans and told the BBC: “People unfortunately need to give us time to get back. It will be two to three seasons.”
Speaking to the Stick to Football podcast, 51-year-old Solskjaer, who managed United from 2018-21, added: “I don’t think there is a magic wand, as in let’s change the owners.
“Obviously they have their certain way of working, the Glazers have still got the commercial [operation] – who knows how it is going to be in football, that side of it.”
United are 19 points behind Premier League leaders Liverpool and 11 behind Aston Villa in fourth.
The FA Cup appears to be their only chance of a trophy this season – they face Liverpool in the quarter-finals on Sunday, 17 March.