SNR reset question

[#1]

Hi
I am about to migrate into Plusnet and was wondering about SNR resets.
Do these
1 Initiate a full retraining period
or
2 Just reset the Default SNR to 6dB
or something else.
Thanks in advance
Ian

[#2]

A SNR reset will Initiate a full retraining period just had one done and I am back on 10 day retraining

[#3]

2 is part of 1