Ask for the underlying documents first: the sponsorship agreement, the I-140G filing and supporting documents submitted through the official portal, the gift instruction and its confirmation, and any notice describing abandonment of status. A consent form that references none of these may leave material consequences unexplained. Ask for the sponsorship agreement's side letters as well. Terms about maintenance charges, transfer mechanics and who bears them are frequently placed in a side letter rather than the main agreement, and a consent form will not mention what it does not incorporate.
Read the paperwork the consent form points at
Documents in this program travel in a chain: fee receipt, USCIS instructions, the I-140G package, vetting outcome, then the gift instruction. Check whether the proposed consent incorporates other terms and whether it concerns sponsorship, a transfer request or actual abandonment of status. Get copies with dates and file numbers, keep your own set, and let counsel compare the wording against the current official instructions before you return anything signed.
Before returning anything, write down in your own words what the form asks you to give up, then compare that against the documents it references. A consent to a transfer request, a withdrawal of sponsorship, and an abandonment of status are three different acts with three different consequences, and one page can be drafted to blur them. Keep a countersigned, dated copy of whatever you sign.