It will not affect anything if you change it properly.

First stop all services related to beacon and service account then disable the task related to Flexera from task scheduler.

After this you can change service account or password. Once this is done you need to change password or service account name and password from all the place you have used.(this need to be check by you before implementation) e.g. SCCM integration, business adapter, IIS Manager, Services, Task scheduler.