How to unstake rETH?

Could you please elaborate on the process of unstaking rETH? I'm interested in understanding the steps involved, as well as any potential considerations or requirements that need to be met. Could you also explain any associated costs or fees that might be involved in the unstaking process? Additionally, it would be helpful to know if there are any specific timeframes or waiting periods that I should be aware of. Thank you for your assistance in clarifying this matter.