She said the pair had often talked about joining forces.
"The further we got into it there were no game breakers, only positives - big advantages for team members, clients and ourselves."
Ms Hill said the practices shared the same philosophies so in a sense it was "the joining together of two families into one bigger family".
After 22 years heading her own practice, she admits it was a big decision.
"[That's why] it was so important that I valued the partners I was going in with," she said.
"It's really nice for me to have someone else on my team. Having people to bounce things off and being able to have some one there for my clients that has the same philosophies.
"It allows us to provide areas of specialisation within our team that are second to none."
Mr Graham said the merger meant BDO would be able to offer clients more of a "one stop shop" service.
"We can have a larger practice providing the full set of advisory services that clients need."
He said there would of course be challenges as the two practices became one.
"But I feel very confident that we have done the homework we needed to do . . . the reasons for the merger are still sound."
Mr Graham said the practice had been in Rotorua for 38 years under various names - becoming BDO Rotorua in 2001.
Although under the BDO brand, BDO Rotorua is locally owned and operated, which was important to Mr Graham and Ms Hill.
Ms Hill admits giving up the ReSolve name initially caused her some "soul searching".
"But people don't come to a firm for a name, they come for the people behind the name."
Reaction from her clients had been 100 per cent positive, she said.
"They love the idea of having a bigger family, greater access to resources and specialists."
After 18 years in their Eruera St offices the move will be the end of an era for ReSolve staff.
"It will be a little bit sad leaving but we are really excited - this is the practice for the future."
The March 1 date was chosen so everything would be "bedded down" in time for the start of the new financial year on April 1, she said.
"We will be in position to roll out without there being any major glitches."