Your English is incorrect, should read, "How do you prune an olive tree?"
prune them
During the Winter.
Prune it during the growing season. but dont cut off any fruiting wood unless you have to.
You can prune it but the symmetrical shape that makes it attractive will be wrecked. If you do prune only tip prune.
If you wanted to prune a tree, you will need a Class 1 fulcrum.
Deciduous trees are best pruned after leaf fall. Evergreens should be trimmed either in Spring or late Summer.
Whict month of the year graft a cherry tree?
winter
The best time to prune an Olive Tree is soon after the fruit has been harvested when the tree is in a more dormant state. Here in Spain many trees are pruned at the same time as the fruit is being picked often with branches cut then shaken for the Olives.
If possible, you should request that your neighbor trim the branches. If you trim them and somehow the tree coincidentally dies, there would be further problems.
well plums start to blom in summer so once they are purple and a little soft that's when you should do it i hope this has helped