Tier2 PBS dependant -Surname addition

[aerovenkat2010]

Hello All,

I am from India working in UK with Tier 2 general VISA and my son 4 Yrs old is also living with me with Tier 2 PBS dependant VISA and our VISAs are due for renewal at end of June 2020.
Meanwhile My son passport doesn't have any surname which we forget to record during the application, hence his BRP card also doesn't have any surname.
In this scenario, if I want to add Surname in his passport in coming months, will it has any impact during his VISA renewal due in June 2020.

If it is case what could be a best advise to add surname in his passport and subsequent VISA update.

Kindly advise.

Thanks in advance.
Venkat