Can you suggest about conflict solving in case there is no role of release manager and team members are located in very different locations all around the world.
If some conflict occurs - it would mean all developers who changed the same PLSQL package should all have live meeting in Skype for example and decide how to solve conflict ?
Good question. If a conflict occurs then what should be done next depends on the complexity of the conflict.
Most conflicts are easy to resolve. The person who is doing the merge can easily resolve these conflicts. (This person can be one of the developers who caused the conflict.)
If the cause of the conflict is more complex, the developers who caused the conflict should communicate with each other. This can be done via email, an issue tracking software or chat etc... it really depends on the complexity of the conflict.
Ideally, when a developer works on a long term task, she should pull from the master repo as often as possible to her local environment and solve any issues locally before releasing her code publicly to be merged with the master code. This way, conflicts occur less often and they are less complicated.
Hope this helps.