Some say ‘it’s all in the name’ while others say, ‘naam mei kya rakha hai’, well either of them apply when a person changes his/her name since he is choosing another name, hence the first saying, at the cost of his/her former name, hence the second one.
Nonetheless, names are the medium for the so-called first impression and as the saying goes ‘first impression is the last’, one, especially if you are famous, will do whatever it takes to make that first impression a remarkable one. Perhaps these were the reasons that compelled the following actors to change their former names to adopt a ‘stage name’ to qualify for the dynamic times or other personal reasons.