I have an on-prem TFS, In that there are too many change-sets are available. Now I'm using Visual Studio Team Services (VSTS) for same project, but I want to integrate my on-prem TFS change-sets also at VSTS. It means, If in my on-prem in have change-set from id 1 to 987, after integrate I want whenever any developer check-in any code in VSTS it start from 988, not from 1.
There is no documented way I am aware of. You have a tiny tiny thin chance going through Microsoft Support by opening a Service Request (i.e. a support ticket) and hope to touch their heart enough. If I were you, I would redesign my tools/process to work around this issue e.g. if you use the changeset number in communication prefix with a letter the numbers from the new system.