A mother-of-five died after she was deliberately pushed down the stairs by her friend in a row over a £200 debt, a court heard.
Linda Rainey, 60, died in hospital two days after suffering a head injury at a flat in Great Yarmouth in August 2019.
A jury at Norwich Crown Court found Rosalind Gray, 54, of Marlborough Square, guilty of her manslaughter.
Gray was also convicted of conspiring to pervert the course of justice along with Adrian Lawrence.
The pair will be sentenced next month.
The court was told an ambulance was called to the home of Lawrence, 55, in South Market Road at about 23:40 BST on 5 August after reports a woman had fallen down stairs.
Ms Rainey was taken to James Paget Hospital with serious head injuries and later transferred to Addenbrooke's Hospital in Cambridge, but died two days later.
On 10 August, the court heard, police received a phone call from a woman who had been drinking with the three friends, claiming she saw Gray push Ms Rainey.
Prosecutor Andrew Jackson QC said Gray had the "propensity to be violent" and had "deliberately" pushed her friend down the stairs.
The two women had discussed going on holiday together and texts revealed a dispute over £200 allegedly owed to the deceased, he said.
The court heard the unnamed witness had been told to hide in a room while the ambulance attended "as she couldn't be trusted to keep quiet".
Gray and Lawrence then "applied more pressure" and met the witness at a pub "to get their story straight", police said.
Gray denied murder.
Det Ch Insp Mike Brown from Norfolk Constabulary said: "Rosalind Gray and Adrian Lawrence immediately knew the seriousness of Rosalind's actions and went to great lengths to cover it up, even after Linda died."