Planning resource without redistributing what is not consumed

Hello,

In MS Project, I wish I could schedule a resource without redistributing the remaining time.

Ex: A person is planned at 50% over a year (i.e. 10 days per month)
In January, the resource only worked 2 days.

MS Project behavior => the system redistributes 8 days until the end of the year after the days entered

Desired behavior => the system must consider 2 days past in January and must not redistribute the 8 days considered as past or lost.

What are the possible options on the tasks in order to be able to simulate the desired behavior?

Thank you in advance for your feedback or answers

Francois