Ruling on performing ‘Umrah on behalf of another in between ‘Umrah and Hajj when doing tamattu’
Question

                I made hajj tamattu this year.can one do umrah on behalf of others in the period between umrah and hajj(by going to tan'nim and assume ihram)?i was told i cannot.i know of people who did hajj tamattu and in the time period between umrah and hajj did many umrahs on behalf of others as well as nafil umrah for themselves. is this ok or not?.
Praise be to Allah.This is permissible, but it is not Sunnah. 
    The Sunnah is for a person not to repeat ‘Umrah during the one trip, rather it is sufficient to perform the ritual once, because that is what the 
    Prophet  (peace and blessings of Allaah be upon him) did. With regard to the person on whose behalf you want to do ‘Umrah, it is better to 
    pray for him. That is the best thing to do in this case.