Looks like father William died.
June 1887 Yarmouth, Vol 4b, page 8
Harrison, William age 47
And mother Rosetta remarried:
March 1888, Yarmouth, Vol 4b, page 23
Harrison, Rosetta
to either
Howlett, Edward John A
or
Stanley, Joseph James
Doesn't explain why Annie moved though!
Meanwhile, 1871 census, reference RG10/1790/8/10
HARRISON, William Head Married M 32 Wood Turner Grantham, Lincs
HARRISON, Rosetta Wife Married F 31 Kings Lynn, Norfolk
HARRISON, William Son Single M 8 Gt Yarmouth
HARRISON, Edward Son Single M 6 months Gt Yarmouth
All at Great Yarmouth
And Annie is with her Aunt in Kings Lynn:
Reference RG1/1865/12/17
GAZELEY, Elizabeth Head ? F 35 Outfitter Kings Lynn
SMITH, Mary Sister Unmarried F 22 Kings Lynn
SMITH, Elizabeth Mother ? F 67 Gooderstone?
HARRISON, Annie Niece F 4 Kings Lynn