In jedi order a padwan is trained under one master, at a time a padwan can not be trained under two masters and a master can not train two padwans.
If a padwan is having his training phase where he/she is not ready for the knighthood trials and his/her master died, what does jedi council or code do with the padwan? does he or she is "transfered" to another master? Does padwan has to stop training and his fate is sealed forever? Does any other high council member [like master yoda] manages to train that padwan until a new master is ready?
Edit: @GorchestopherH Has given a nice feedback with example
There are lots of cases where we see strict Jedi rules regarding who can be trained, but we also see that rules are bent almost all the time. It's difficult to know what official policy is with counter-examples flying in its face. Consider Luke, the most popular example. Obi Wan trained him, then when he died, Yoda did.
This is the case where there are very few jedi remaining and they have to bend the rules in order to survive. But what about Galactic republic era, where Jedi order is strictly followed by their code?