Merging the same individual
In my family tree I have Thomas Rowland born 1808 in UK died 1880 in Oswego Illinois.
My Thomas is LZJL-QH2
Another researcher in the US has built a tree which also feature the same Thomas Rowland
His Thomas is 3SFB-QYJ.
We have both tried to merge these two trees to link them to the same Thomas Rowland but without success.
How can we do this please?