(Reuters) - U.S. President-elect Joe Biden has promised a quick and dramatic reversal of the restrictive immigration policies put in place by his predecessor President Donald Trump. While Biden pledged to undo many of Trump’s policies starting the first day he takes office on Jan. 20, the layers of reforms will take much longer to implement. IMMIGRATION REFORM AND ‘DREAMERS’ Biden, a Democrat, said in a June tweet he will send a bill to Congress “on day one” that laid out “a clear roadmap to citizenship” for some 11 million people living in the United States unlawfully. Biden has said he would create permanent protection for young migrants in the Deferred Action for Childhood Arrivals (DACA) program, known as “Dreamers.” Started by former President Barack Obama when Biden was vice president, the program currently provides deportation protection and other benefits to approximately 645,000 people. Trump’s Republican administration tried to end DACA but was stymied in federal court. The program still faces a legal challenge in a Texas court. Vice president-elect Kamala Harris said in an interview with Univision on Jan. 12 that the administration planned to shorten citizenship wait times and allow DACA holders, as well as recipients of Temporary Protected Status (TPS), to “automatically get green cards,” but did not explicitly say when or how these changes would happen. Trump moved to phase out TPS, which grants deportation protection and allows work permits to people from countries hit by natural disasters or armed conflict. Earlier in his campaign, Biden promised to “immediately” grant TPS to Venezuelans already in the United States. For years lawmakers have failed to pass a major immigration bill. Democrats may stand a better chance of passing legislation after a run-off election in Georgia handed them control of both houses of Congress. RESTORING ASYLUM AND REFUGEES Trump blasted what he called “loopholes” in the asylum system and implemented overlapping polices to make it more difficult to seek refuge in the United States. One Trump program called the Migrant Protection Protocols (MPP) forced tens of thousands of asylum seekers to wait in Mexico for hearings in U.S. immigration court. Biden said during the campaign he would end the program on day one. His transition team, however, has said dismantling MPP and restoring other asylum protections will take time. Under rules put in place by the U.S. Centers for Disease Control during the coronavirus pandemic, most migrants arriving at the border are now immediately expelled. Biden’s team has not pledged to reverse that policy right away. Migrant caravans have been on the move in Central America, with some aiming to arrive at the southwest border after Biden’s inauguration. Advocates worry that the pandemic will make it difficult for border officials and migrant shelters to handle large numbers of people. Biden has also said he would raise the cap for refugees resettled in the United States from abroad to 125,000 from the historic low-level of 15,000 set by Trump this year. FAMILY REUNIFICATION Biden’s transition team promised to immediately create a federal task force to reunify children separated from their parents under one of the Trump administration’s most controversial policies. Thousands of children were separated from their parents when Trump implemented a “zero tolerance” policy of prosecuting all border crossers, including families, for illegal entry. Though Trump officially reversed the policy in June 2018 amid international outcry, some children have continued to be separated for other reasons. Advocates are still searching for the parents of more than 600 separated children. TRAVEL AND VISA BANS One of Trump’s first actions after taking office in 2017 was banning travel from several Muslim-majority countries. Following legal challenges, the U.S. Supreme Court upheld a revised version of the ban in 2018. It has since been expanded to 13 nations. Biden has promised to immediately rescind the bans, which were issued by executive actions and could be easily undone, according to policy experts. During the coronavirus pandemic Trump issued proclamations blocking the entry of many temporary foreign workers and applicants for green cards. While Biden has criticized the restrictions, he has not yet said whether he would immediately reverse them. BORDER WALL Biden pledged to immediately halt construction of the U.S.-Mexico border wall, which Trump touted as a major accomplishment during a Texas visit just days before leaving office. It is not entirely clear what Biden’s administration will do with contracts for wall construction that have already been awarded but have yet to be completed, or with private land seized by the government in places where building has stopped. (This story corrects paragraph 17 to clarify the measures blocked green card applicants).