Hi @VinoM,
Not sure what do you mean by responses, approvals and such? Because the way you wrote this it seems like you need their response so not sure if this is in written form (which would be hard to get if they are absent) or just approval to keep the things rolling.
If this is related to approval there is always an option to delegate the approval for any period, this period can be edited and delegation can also be cut short if needed, please check the following screenshot.

All that is needed is to select to who you want to delegate to, and the date range for the delegation.
Another option is to use log in as option available for the system administrator and do the actions on the behalf of the person (in the system log it will say for example Vino Approved ... on behalf of ...).
You can also use the email notifications and automatic remainders but I am not sure if the user will benefit from this as they are absent, please check the following screenshots

Hopefully this helps. Have a great day.
Best regards,
Ivan Bebek