Here in this question two different things asked first is 
transfers means on same post, with same salary a person 
ordered by some one or higher authority to go any other 
branch this is called transferes and reasons of transfer is 
nonavaibility of sufficent staff in other branch and/or 
other branch needs transferee's knowledge and many other 
qualities. Thus, reasons of transfer at the same time and 
at other hand promotion means ordered any person to go uper 
level from his running post in the same branch but wity 
salary as well as liability because of his good, hard and 
appriciate work. Thus this is tdefinition and reasons for 
transfers and promotion.